Dr Guillaume Fond
email: guillaume.fond@ap-hm.fr

MD Vanessa Pauly

PhD Veronica Orleans

Msc François Antonini

MD Cyprien Fabre

MD Michel Sanz

Msc Sophie Klay

Msc Marie- Thérèse Jimeno

MD Marc Leone

MD PhD Christophe Lancon

PhD Pascal Auquier

PhD Laurent Boyer

Increased in-hospital mortality from COVID-19 in patients with schizophrenia COVID-19 mortality in schizophrenia

Keywords: Schizophrenia, Psychiatry, COVID-19, observational study ICU: intensive care unit. p-value in bold: statistical significance

Background. There is limited information describing the presenting characteristics and outcomes of patients with schizophrenia (SCZ) requiring hospitalization for coronavirus disease 2019 .

Aims. We aimed to compare the clinical characteristics and outcomes of COVID-19 SCZ patients with those of non-SCZ patients.

Method. This was a case-control study of COVID-19 patients admitted to 4 APHM/AMU acute care hospitals in Marseille, southern France. COVID-19 infection was confirmed by a positive result on polymerase chain reaction testing of a nasopharyngeal sample and/or on chest computed scan among patients requiring hospital admission. The primary outcome was in-hospital mortality. The secondary outcome was intensive care unit (ICU) admission.

Results. A total of 1092 patients were included. The overall in-hospital mortality rate was 9.0%. The SCZ patients had an increased mortality compared to the non-SCZ patients (26.7% vs. 8.7%, p=0.039), which was confirmed by the multivariable analysis after adjustment for age, sex, smoking status, obesity and comorbidity (adjusted odds ratio 4.36 [95% CI 1.09-17.44]; p=0.038). In contrast, the SCZ patients were not more frequently admitted to the ICU than the non-SCZ patients. Importantly, the SCZ patients were mostly institutionalized (63.6%, 100% of those who died), and they were more likely to have cancers and respiratory comorbidities.

Conclusions. This study suggests that SCZ is not overrepresented among COVID-19 hospitalized patients, but SCZ is associated with excess COVID-19 mortality, confirming the existence of health disparities described in other somatic diseases.

Introduction

Only five months after the appearance of COVID-19, the disease caused by the coronavirus that appeared in China in December 2019, France has been bearing the full brunt of the health crisis that has been unleashed across the planet. On January 24 th , 2020, the French Ministry of Health reported the first two cases in France; both were infected in China, where they had recently traveled. The first death due to the COVID-19 was registered on February 14 th , 2020, in an older Chinese tourist. The next day, a religious demonstration brought 2,000 people together in the town of Mulhouse in East France, which was likely to be the starting point for serial contamination throughout the country, from Corsica to French Guiana, and from the Hautes-Alpes to Normandy and the Ile-de-France region. On April 4 th , France reached an unprecedented milestone: 6,838 patients were hospitalized in intensive care unit (ICU), a record "in French medical history" [START_REF]Coronavirus : des premiers cas au premier mois de confinement, les principales étapes de l'évolution de l'épidémie en France[END_REF].

Among all specific populations that may have a particularly poor COVID-19 outcome, patients with schizophrenia (SCZ) should be given particular attention. Since the Second World War, when SCZ patients died massively in asylums from malnutrition (the so-called "extermination douce" (gentle extermination)(2)), the somatic care of patients with SCZ has lagged behind that of other mentally healthy patients. We have recently found, in a national database study, that patients with schizophrenia received less high-intensity care than those without severe mental disorder [START_REF] Fond | End-of-life care among patients with schizophrenia and cancer: a population-based cohort study from the French national hospital database[END_REF], and it is unknown whether COVID-19 patients with SCZ benefit from the same care as non-SCZ patients. In summary, COVID-19 may strongly impact SCZ patients and the health and economic disparities they experience [START_REF] Kozloff | The COVID-19 Global Pandemic: Implications for People With Schizophrenia and Related Disorders[END_REF].

It also remains unknown whether SCZ is a risk factor for COVID-19 infection and/or COVID-19 mortality. Among COVID-19 risk factors, presence of comorbidities, poor insight into somatic symptoms, stigma experience, delusions and cognitive impairment leading to a misperception of the risk related to the virus have been identified [START_REF] Kozloff | The COVID-19 Global Pandemic: Implications for People With Schizophrenia and Related Disorders[END_REF]. The prevalence of tobacco smoking is higher in patients with SZ than in the general population, with higher rates of heavy smokers and nicotine dependence( 5), yet it remains unclear whether smoking is a protective factor or a risk factor for COVID-19 infection and mortality [START_REF] Cattaruzza | Tobacco Smoking and COVID-19 Pandemic: Old and New Issues. A Summary of the Evidence From the Scientific Literature[END_REF]. Hypovitaminosis D has been identified in 27% of patients with SCZ vs. 21% of the general population [START_REF] Fond | Hypovitaminosis D is associated with negative symptoms, suicide risk, agoraphobia, impaired functional remission, and antidepressant consumption in schizophrenia[END_REF], yet it remains unknown whether hypovitaminosis D may modify the risk for COVID-19 infection and/or mortality [START_REF] Grant | Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths[END_REF]. SCZ is also a risk factor for homelessness or institutionalization, which may mediate the risk for increased COVID-19 infection and/or mortality [START_REF] Ayano | The Prevalence of Schizophrenia and Other Psychotic Disorders Among Homeless People: A Systematic Review and Meta-Analysis[END_REF]. In addition to these multiple risk factors for poor COVID-19 outcomes, active social withdrawal is one of the most frequent negative symptoms of SCZ that may protect noninstitutionalized patients from infection through spontaneous lock-down and social distancing.

The objective of the present study was to compare the presenting characteristics and outcomes of COVID-19 patients with SCZ with COVID-19 patients without SCZ.

Methodology

Setting

This study was conducted at Assistance Publique -Hôpitaux Marseille (APHM) -Aix-Marseille University (AMU), a quaternary, acute care hospital system in Marseille, southern France. APHM/AMU comprises four hospitals (La Timone, La Conception, Sainte-Marguerite, and North), 3,400 beds, and 2,000 physicians. Approximately 300,000 hospitalizations are recorded every year, involving approximately 200,000 patients. All consecutive patients who were sufficiently medically ill to require hospital admission with confirmed COVID-19 infection by positive result on polymerase chain reaction testing (PCR) of a nasopharyngeal sample and/or by chest computed scan (i.e., extended bilateral ground-glass opacities and area of consolidation) were included. Eligible patients were admitted to any of 4 APHM/AMU acute care hospitals from February 27, 2020, to April 15, 2020. Clinical outcomes were monitored until May 4, 2020, the final date of follow-up. The APHM/AMU institutional review board (CADS) approved this work as minimal-risk research using data collected for routine clinical practice (CADS identifier: Q7APAN-M9GR8M-2020).

Data sources and collection

Data were obtained from the APHM/AMU clinical data warehouse. This warehouse contains all the clinical data available on all inpatient visits to one of the APHM/AMU facilities. No data were manually abstracted from the electronic medical record or charts. The data obtained included patients' sociodemographic data, clinical data (i.e., smoking status, overweight and obesity, symptoms, Charlson comorbidity index score [START_REF] Bannay | The Best Use of the Charlson Comorbidity Index With Electronic Health Care Database to Predict Mortality[END_REF] and main comorbidities), triage vital signs, initial laboratory test results, initial COVID-19 treatment, ICU admission, Simplified Acute Physiology Score II (SAPS II), length of ICU stay and ICU management (i.e., mechanical ventilation, renal replacement therapy), palliative care, and outcomes (i.e., length of hospital stay and in-hospital mortality). Clinical data, ICU admission and treatments, palliative care and outcomes were based on the 10th revision of the International Statistical Classification of Diseases (ICD10) and procedural codes were based on the classification commune des actes médicaux (CCAM) associated the French from the Programme de Medicalisation des Systèmes d'Information (PMSI) -French medico-administrative database based on diagnosis related-groups (DRGs). The Charlson comorbidity index predicts 10-year survival in patients with multiple comorbidities and was used as a measure of total comorbidity burden [START_REF] Bannay | The Best Use of the Charlson Comorbidity Index With Electronic Health Care Database to Predict Mortality[END_REF]. The protocol recommended by a medical team from Marseilles for COVID-19 treatment was a combination of hydroxychloroquine (200 mg of oral hydroxychloroquine, three times daily for ten days) and azithromycin (500 mg on day 1 followed by 250 mg daily for the next four days) [START_REF] Gautret | Clinical and microbiological effect of a combination of hydroxychloroquine and azithromycin in 80 COVID-19 patients with at least a six-day follow up: A pilot observational study[END_REF] thus explaining the important amount of this prescription in our study.

Definition of cases and controls

Cases were patients who had a diagnosis of SCZ according to specific ICD10 codes (i.e., F20*, F22*, or F25*). Controls were patients who did not have a diagnosis of mental illness according to specific ICD10 codes in the acute care database and who were not listed in the psychiatry databases.

Outcomes

The primary outcome was in-hospital mortality. The secondary outcome was ICU admission.

Statistical analysis

Continuous variables were expressed as medians and interquartile ranges. Categorical variables were summarized as counts and percentages. No imputation was made for missing data.

We used either the χ2 or Fisher's exact test and Student's t test or Mann-Whitney test to compare sociodemographic data, clinical data, triage vital signs, initial laboratory test results, initial COVID-19 treatment, ICU admission and treatments, palliative care, and outcomes between cases and controls. Then, multivariable logistic regression models were used to estimate the association between schizophrenia and the two endpoints. An initial multivariable regression model (model 1) included the main known prognostic factors: age, sex, smoking status, overweight and obesity, and Charlson comorbidity index. Two additional models were also performed, including prognosis factors previously listed and the two main COVID-19 treatments delivered in our institution (model 2: hydroxychloroquine and model 3: hydroxychloroquineazithromycin combination). A significance threshold of p<0.05 was used. All analyses were performed in SAS (version 9.4).

Results

Characteristics of the patients

During the study period, a total of 1092 patients were included in the analysis (median age, 63 years [interquartile range [IQR], 51-76]; 46.7% female with no significant differences between SCZ and non-SCZ), with 15 SCZ patients (frequency=1.37%, 95% confidence interval (CI) from 0.68 to 2.06) and 1077 non-SCZ patients (98.63%) (Figure 1, Table 1). The SCZ patients were more likely to be smokers (33.3%vs.11.1%, p=0.021) and to have cancers (20.0%vs. 5.5%, p=0.049) and respiratory comorbidities (26.7%vs.4.9%, p=0.006) than the non-SCZ controls. The SCZ patients had a higher level of creatinine kinase (213.5 IU/L vs. 98.0 IU/L, p=0.015) and a lower level of total bilirubin (4.5 µmol/L vs. 7.0 µmol/L, p=0.006) than the non-SCZ controls. A qualitative analysis of the 15 SCZ patients is presented in Supplementary Table S1. They were mostly institutionalized (63.6%, 100% of those who died) and elderly. The length of hospital stay was similar in the SCZ and non-SCZ patients (median [IQR] 10 days [START_REF] Fond | Hypovitaminosis D is associated with negative symptoms, suicide risk, agoraphobia, impaired functional remission, and antidepressant consumption in schizophrenia[END_REF][START_REF] Grant | Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths[END_REF][START_REF] Ayano | The Prevalence of Schizophrenia and Other Psychotic Disorders Among Homeless People: A Systematic Review and Meta-Analysis[END_REF][START_REF] Bannay | The Best Use of the Charlson Comorbidity Index With Electronic Health Care Database to Predict Mortality[END_REF][START_REF] Gautret | Clinical and microbiological effect of a combination of hydroxychloroquine and azithromycin in 80 COVID-19 patients with at least a six-day follow up: A pilot observational study[END_REF][START_REF] Moreno-Küstner | Prevalence of psychotic disorders and its association with methodological issues. A systematic review and meta-analyses[END_REF][START_REF] Saha | A systematic review of the prevalence of schizophrenia[END_REF][START_REF] Lawrence | Inequalities in healthcare provision for people with severe mental illness[END_REF][START_REF] Vancampfort | The impact of pharmacological and non-pharmacological interventions to improve physical health outcomes in people with schizophrenia: a meta-review of meta-analyses of randomized controlled trials[END_REF] vs. 7 [START_REF] Kozloff | The COVID-19 Global Pandemic: Implications for People With Schizophrenia and Related Disorders[END_REF][START_REF] Sagud | Smoking in Schizophrenia: Recent Findings About an Old Problem[END_REF][START_REF] Cattaruzza | Tobacco Smoking and COVID-19 Pandemic: Old and New Issues. A Summary of the Evidence From the Scientific Literature[END_REF][START_REF] Fond | Hypovitaminosis D is associated with negative symptoms, suicide risk, agoraphobia, impaired functional remission, and antidepressant consumption in schizophrenia[END_REF][START_REF] Grant | Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths[END_REF][START_REF] Ayano | The Prevalence of Schizophrenia and Other Psychotic Disorders Among Homeless People: A Systematic Review and Meta-Analysis[END_REF][START_REF] Bannay | The Best Use of the Charlson Comorbidity Index With Electronic Health Care Database to Predict Mortality[END_REF][START_REF] Gautret | Clinical and microbiological effect of a combination of hydroxychloroquine and azithromycin in 80 COVID-19 patients with at least a six-day follow up: A pilot observational study[END_REF][START_REF] Moreno-Küstner | Prevalence of psychotic disorders and its association with methodological issues. A systematic review and meta-analyses[END_REF][START_REF] Saha | A systematic review of the prevalence of schizophrenia[END_REF][START_REF] Lawrence | Inequalities in healthcare provision for people with severe mental illness[END_REF] p=0.196).

In-hospital Mortality

The overall in-hospital mortality rate was 9.0%. The univariable analysis is presented in Supplementary Table S2. SCZ patients had an increased mortality compared to non-SCZ patients (26.7% vs. 8.7%, p=0.039) (Table 2), which was confirmed by the multivariable analysis after adjustment for age, sex, smoking status, obesity and Charlson comorbidity index (model 1) (adjusted odds ratio (aOR) 4.36 [95% CI 1.09-17.44]; p=0.038) (Table 3). The additional models (2 and 3) reported the same findings.

ICU admission

A total of 191 patients (17.5%) were admitted to the ICU (median SAPS II, 34.5 [IQR], 29-43; median SAPS II in the non-SCZ-patients, 35.0

[IQR], 29-43; and SAPS II in the two SCZ patients were 25 and 34 respectively). The univariable analysis is presented in Supplementary Table S3.

The SCZ patients were not more frequently admitted to the ICU than the non-SCZ patients (13.3% vs. 17.6%, p=0.265; aOR 0.46 [95% CI 0.10-2.18]; p=0.330) (model 1) (Table 3). The additional models (2 and 3) reported the same findings. None of the deceased SCZ patients were admitted to ICU vs. 28.7% (27/94) for non SCZ patients. The median length of ICU stay was 12.0 [IQR], 4.0-28.0, 13.0[IQR], (4.0-28.0) in the non-SCZ patients and the length of ICU stay for the 2 SCZ patients was 3 days and 5 days respectively.

Discussion

To our knowledge, this study is the first preliminary cohort of sequentially hospitalized confirmed COVID-19 patients with SCZ and non-SCZ. The mortality of the SCZ patients was 3 times higher than that of the non-SCZ patients after adjustment for age, sex, smoking status, obesity and comorbidities.

The first major finding of this study is that SCZ is not overrepresented among COVID-19 hospitalized patients compared to the prevalence of SCZ in the general population (between 0.5 and 1.5% in most countries) [START_REF] Moreno-Küstner | Prevalence of psychotic disorders and its association with methodological issues. A systematic review and meta-analyses[END_REF][START_REF] Saha | A systematic review of the prevalence of schizophrenia[END_REF]. Our data do not suggest that SCZ patients are more at risk of COVID-19 than the general population, contrary to what could have been expected(4). However, we cannot rule out the possibility of a higher risk of COVID-19 in SCZ patients outside the hospital who have poor access to hospital care [START_REF] Lawrence | Inequalities in healthcare provision for people with severe mental illness[END_REF] and/or out-of-hospital deaths. Future studies should estimate the prevalence and management of COVID-19 for SCZ patients outside the hospital. SCZ was associated with excess mortality after adjustment for age, sex, smoking status, obesity and comorbidity, underlining the existence of health disparities in COVID-19 as already described in other somatic diseases [START_REF] Fond | End-of-life care among patients with schizophrenia and cancer: a population-based cohort study from the French national hospital database[END_REF][START_REF] Vancampfort | The impact of pharmacological and non-pharmacological interventions to improve physical health outcomes in people with schizophrenia: a meta-review of meta-analyses of randomized controlled trials[END_REF]. Previous studies reported health care disparities in SCZ patients [START_REF] Mitchell | Quality of medical care for people with and without comorbid mental illness and substance misuse: systematic review of comparative studies[END_REF]. A delay in access to hospital care may be suggested by the higher respiratory rate at admission in patients with SCZ patients compared to non-SCZ patients. Respiratory rate has been reported as an important indicator of serious illness [START_REF] Cretikos | Respiratory rate: the neglected vital sign[END_REF]. However, we have no precise information on the delay between the onset of infection and hospitalization. Further studies will need to explore access to hospital care in SCZ patients with COVID-19. In our study, we found no differences in the treatment protocol administered to SCZ patients compared to non-SCZ patients, and increased mortality remained significant after adjustment for treatment administration. We found no difference in access to the ICU. However, none of the SCZ patients who died were admitted to the ICU, which would deserve to be better understood: advanced age and co-morbidities, cognitive impairment or death occurring before ICU admission (for instance massive pulmonary embolism)(3). Factors consistently found in the literature to be associated with a decision to admit or refuse a patient to the ICU are bed availability, severity of illness, initial ward or team the patient was referred from, patient preference, do not resuscitate order status, age and functional status at baseline [START_REF] James | Decision-making in intensive care medicine -A review[END_REF]. Future studies (based on qualitative studies with ICU clinicians and national medico-administrative studies) should thus explore ICU admission in SCZ patients with COVID-19.

One major finding emerging from the qualitative analysis is that around two thirds of the SCZ patients were institutionalized, and 100% of the SCZ patients who died were institutionalized. We lack national data on the rate of elderly SCZ patients who are institutionalized, yet we can reasonably hypothesize that institutionalization is a risk factor for COVID-19 severe infection in elderly patients with SCZ. Hence preventive measures should target this population. Contrary to what could have been expected, the SCZ patients were not younger than the non-SCZ patients, while their life expectancy is generally reduced compared to the general population [START_REF] Samaras | Premature Mortality and Schizophrenia-The Need to Heal Right From the Start[END_REF]. This result is also in favor of a risk increase in institutionalized SCZ patients and against an increased risk of COVID-19 infection in the global SCZ population. However, these results should be interpreted with caution, as we only identified 15 SCZ patients, and these results should be replicated in future wider databases. Our results support a strategy of systematic detection in institutionalized SCZ patients. This has already been done in a homeless shelter in Boston where 36% of the residents tested positive [START_REF] Baggett | Prevalence of SARS-CoV-2 Infection in Residents of a Large Homeless Shelter in Boston[END_REF].

Limitations

This study had several limitations. First, the study population only included patients within the Marseilles metropolitan area, which may limit the generalizability of these results. Second, the sample size for the SCZ patients was limited (N=15). However, this first description of real-life data in patients with SCZ could be shared with other institutions and countries to achieve a larger sample and to provide a more complete picture of SCZ and COVID-19 [START_REF] Boyer | Real-life data and Covid-19: The third avenue of reseach[END_REF]. Third, the data were collected from the electronic health record database. This precluded the level of detail that would have been possible with a manual medical record review. Additional limitations of our study include missing data for some variables and potential for inaccuracies in the electronic health records.

Strengths

This study is the first to explore the in-hospital mortality of SCZ patients due to COVID-19 infection. The results were adjusted for important confounding factors and suggest a remaining 3-fold increase in in-hospital mortality risk in SCZ patients.

Conclusion

This study suggests that SCZ may not be overrepresented among COVID-19 hospitalized patients compared to the prevalence of SCZ in the general population but that SCZ is associated with increased in-hospital mortality, confirming the existence of health disparities as already described in other somatic diseases. COVID-19 seemed to affect mostly institutionalized and elderly patients. These real-life health data should be shared with other health data producers to achieve a larger sample and to provide a more complete picture of SCZ and COVID-19.

*

  If Body Mass Index (BMI) is 18.5 to <25: normal weight; If BMI is 25.0 to <30: overweight; If BMI is 30.0 or higher: obesity. Symptoms and comorbidities based on the 10th revision of the International Statistical Classification of Diseases from the Programme de Medicalisation des Systèmes d'Information (PMSI) -French medico-administrative database based on diagnosis related-groups (DRG). p-value in bold: statistical significance.

Table 1 .

 1 Baseline Characteristics of Patients Hospitalized With COVID-19 (n=1092).

	Characteristics	Total	SCZ patients	Non-SCZ	p-value
				patients
		n=1092	n=15	n=1077
		n(%)	n(%)	n(%)
	Socio-demographic data
	Age, median (IQR) -yr	62.5(51.0-76.0)	66.0(63.0-	62.0(51.0-	0.345
			72.0)	76.0)
	<18 yr	19(1.7)	0(0.0)	19(1.8)	0.714
	18-65 yr	587(53.8)	7(46.7)	580(53.9)
	>65 yr	486(44.5)	8(53.3)	478(44.4)
	Male sex -no. (%)	593(54.3)	11(73.3)	582(54.0)	0.136
	Clinical data
	Smoker	125(11.5)	5(33.3)	120(11.1)	0.021
	Weight*				0.710
	Normal weight	749(68.6)	10(66.7)	739(68.6)
	Overweight	128(11.7)	1(6.7)	127(11.8)
	Obesity	215(19.7)	4(26.7)	211(19.6)
	Symptoms
	Agueusia and/or anosmia	184(16.9)	2(13.3)	182(16.9)	0.999
	Digestive symptoms	250(22.9)	4(26.7)	246(22.8)	0.758
	(Diarrhea and/or nausea
	or vomiting)
	Respiratory symptoms	795(72.8)	11(73.3)	784(72.8)	0.999
	(cough and/or pharyngitis
	and/or dyspnea and/or
	hemoptysis)
	General symptoms	532(48.7)	3(20.0)	529(49.1)	0.025
	(asthenia and/or
	headache and/or
	myalgia/arthralgia)
	Comorbidities

Initial laboratory findings, median

  Table2. Clinical outcomes and management of patients hospitalized with COVID-19 (n=1092).

		Total	SCZ patients	Non-SCZ	p-value
			n=15	patients
		n=1092	n(%)	n=1077
		n(%)		n(%)
	Outcomes and management
	In-hospital mortality	98(9.0)	4(26.7)	94(8.7)	0.038
	ICU admission	191(17.5)	2(13.3)	189(17.6)	0.999
	Recourse to mechanical ventilation	106(9.7)	1(6.7)	105(9.8)	0.999
	Recourse to continuous renal-	21 (1.9)	0(0.0)	21 (2.0)	0.999
	replacement therapy
	Palliative care	49(4.5)	1(6.7)	48(4.5)	0.500
	Characteristics of stay
	Length of ICU stay, median (IQR)-no.
	of days

Acknowledgment. David Braunstein, Myriam Dubuc, Alexandra Murcia, Gilbert Pironti, Vincent Pradel, Anne Remacle, Fanny Romain, Catherine Seyler, Françoise Volot and all the other members of the Department of Medical Information, Bruno Lacarelle and Amin Ben Lassoued (Biology), Martine Charbit (Pharmacy), Alain Lavit, Christophe Rozier (DSN), and all the health care professionals for their great work during the COVID-19 pandemic. Funding. This work was funded by Assistance Publique -Hôpitaux Marseille (APHM) -Aix-Marseille University (AMU) and the European Health Data & Evidence Network from the European Union's Horizon 2020 research and innovation program.

Author Contributions.

Veronica Orleans and Vanessa Pauly had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Laurent Boyer, Guillaume Fond.

Acquisition, analysis, or interpretation of data: Pascal Auquier, Laurent Boyer, Christophe Lancon, Guillaume Fond, Vanessa Pauly, Veronica Orleans, Sophie Klay, Michel Sanz, Cyprien Fabre, Marc Leone.

Drafting of the manuscript: Laurent Boyer, Guillaume Fond.

Critical revision of the manuscript for important intellectual content: All the authors.

Statistical analysis: Vanessa Pauly.

Administrative, technical, or material support: Veronica Orleans and Michel Sanz. Supervision: Laurent Boyer.

Conflicts of interest.

No conflicts to disclose.


Clara Yzet

Momar Diouf

Siddarth Singh

Franck Brazier

Justine Turpin

Eric Nguyen-Khac

Jonathan Meynier

MD Mathurin Fumery
email: fumery.mathurin@chu-amiens.fr

No Benefit of Concomitant Immunomodulator Therapy on Efficacy of Biologics That Are Not Tumor Necrosis Factor Antagonists in Patients With Inflammatory Bowel Diseases: A Meta-analysis

Keywords: Inflammatory bowel disease (IBD), Crohn's disease (CD), ulcerative colitis (UC integrin inhibitor, interleukin, anti-IL12-23, CD, UC

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Since 2000, biologics have revolutionized the therapeutic strategies for inflammatory bowel diseases (IBD). For many years, the available biological therapies were restricted to anti-tumor necrosis factor (anti-TNF) agents. Anti-TNF and immunomodulator combination therapy were identified early as the gold standard, with clinical trial data demonstrating that combination therapy was superior to monotherapy [START_REF] Colombel | Infliximab, Azathioprine, or Combination Therapy for Crohn's Disease[END_REF][START_REF] Feagan | Methotrexate in combination with infliximab is no more effective than infliximab alone in patients with Crohn's disease[END_REF](3). Combination therapy was associated with improved anti-TNF drug pharmacokinetics (higher median trough serum concentrations) and lower immunogenicity, identified as one of the main causes of loss of response [START_REF] Colombel | Infliximab, Azathioprine, or Combination Therapy for Crohn's Disease[END_REF][START_REF] Feagan | Methotrexate in combination with infliximab is no more effective than infliximab alone in patients with Crohn's disease[END_REF][START_REF] Kennedy | Predictors of anti-TNF treatment failure in anti-TNF-naive patients with active luminal Crohn's disease: a prospective, multicentre, cohort study[END_REF].

Over the past decade, vedolizumab (anti-integrin α4β7) and then ustekinumab (antiinterleukin 12/23) were successively approved for treatment of Crohn's disease (CD) and Ulcerative Colitis (UC) [START_REF] Feagan | Vedolizumab as induction and maintenance therapy for ulcerative colitis[END_REF][START_REF] Sandborn | Vedolizumab as induction and maintenance therapy for Crohn's disease[END_REF][START_REF] Sands | Ustekinumab as Induction and Maintenance Therapy for Ulcerative Colitis[END_REF][START_REF] Feagan | Ustekinumab as Induction and Maintenance Therapy for Crohn's Disease[END_REF]. The current evidence and clinical experience with anti-TNF agents raised the idea that all biologics may optimally be used in combination with immunomodulators. However, the evidence supporting the use of combination therapy with these new biologics are limited and conflicting. These drugs are less immunogenic and it is not certain that adding an immunomodulator improves their efficacy [START_REF] Feagan | Vedolizumab as induction and maintenance therapy for ulcerative colitis[END_REF][START_REF] Sandborn | Vedolizumab as induction and maintenance therapy for Crohn's disease[END_REF][START_REF] Adedokun | Ustekinumab Pharmacokinetics and Exposure Response in a Phase 3 Randomized Trial of Patients With Ulcerative Colitis: Ustekinumab PK and exposure-response in UC[END_REF][START_REF] Hanauer | IM-UNITI: Three-year Efficacy, Safety, and Immunogenicity of Ustekinumab Treatment of Crohn's Disease[END_REF][START_REF] Löwenberg | Vedolizumab Induces Endoscopic and Histologic Remission in Patients With Crohn's Disease[END_REF]. On the other hand, the addition of an immunomodulator may be deleterious due to increased risk of serious and opportunistic infections [START_REF] Lemaitre | Association Between Use of Thiopurines or Tumor Necrosis Factor Antagonists Alone or in Combination and Risk of Lymphoma in Patients With Inflammatory Bowel Disease[END_REF][START_REF] Kirchgesner | Risk of Serious and Opportunistic Infections Associated With Treatment of Inflammatory Bowel Diseases[END_REF].

Hence, we aimed to evaluate the comparative effectiveness and safety of using vedolizumab or ustekinumab monotherapy vs. in combination with an immunomodulator in patients with IBD through a systematic-review and metaanalysis.

Methods

This systematic review followed the preferred reporting items for systematic reviews and meta-analysis (PRISMA) standards, and followed an a priori protocol.

Selection Criteria

Studies meeting the following criteria were included: randomized controlled trials, observational cohort in (b) adult patients (c) with a diagnosis of IBD, CD or UC (d) treated with vedolizumab or ustekinumab (e) reporting the rate of clinical response or remission, endoscopic response or remission, or safety, (f) in patients treated with and without combination therapy with an immunomodulator including thiopurines or methotrexate. We excluded studies that did not report clearly outcomes stratified by mono or combination therapy, or that did not provide adequate information to allow estimation of difference in outcomes. When multiple studies from the same cohort were reported, then the most comprehensive report providing information of interest was included.

Search Strategy

We conducted a comprehensive search of multiple electronic databases through, July 2019, with no language restrictions using the following search terms: ("IBD" OR "UC" OR "CD") AND ("vedolizumab" OR "ustekinumab"). The databases included: Ovid Medline, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, and Scopus. The search strategy was designed and conducted by an experienced medical librarian with input from the study investigators, using controlled vocabulary supplemented with keywords. In addition, conference abstracts (Digestive Disease Week, United European Gastroenterology Week, and European Crohn's and Colitis Organization annual meeting) from 2014 to 2019, as well as bibliography of the selected articles and review articles on the topic were manually searched for additional studies, with no language restrictions. Two reviewers (CY and MF) independently assessed the title and abstract of studies identified in the primary search for inclusion (Level 1 screen), and the full text of remaining articles were examined to determine whether they met inclusion criteria (Level 2 screen). Any discrepancy in article selection was resolved by consensus and in discussion with a third reviewer (FB). A reviewer (MF) contacted the primary study authors as needed for additional data or missing information. definition, timepoint of evaluation. For each outcome were collected Odds Ratio (OR), Relative Risk (RR), rate ratios for combination and monotherapy group (comparator), together with their 95% confidence intervals (CI), were recorded. When several adjustment models were reported, the most adjusted estimates were used in the analysis. When only raw event rates were reported, the numbers of events in the groups compared were extracted. Any discrepancies were addressed by a joint re-evaluation of the original article. A quality assessment for observational studies was conducted for studies included in the meta-analysis using the NewCastle Ottawa Scale. For RCTs, risk of bias assessment was conducted using the tool developed by the UK's National Institute for Health and Care Excellence (NICE; https://www.nice.org.uk/process/pmg24/chapter/clinical-effectiveness).

Data Abstraction and

Outcomes Assessed

The primary effectiveness outcome was the clinical benefit including clinical remission, clinical response or global physician judgement (as defined in individual studies) in IBD patients with combination therapy as compared to those who were not. We then evaluated each of these outcomes individually. Secondary outcomes measures were endoscopic improvement as defined by endoscopic remission, response or histologic remission. Primary safety outcome was defined by the risk of adverse events as defined in individual studies. Sub-group analyses were performed by type of IBD (UC / CD), by induction / maintenance treatment, by study design (randomized controlled trial vs observational studies, and prospective vs retrospective studies), as for serious infection.

Statistical Analysis

Assuming inherent heterogeneity between studies, we used the random-effects model described by DerSimonian and Laird to calculate pooled OR (and 95% CI) of study endpoints [START_REF] Dersimonian | Meta-analysis in clinical trials[END_REF]. We assessed heterogeneity between study-specific estimates using the inconsistency index (I2), with cut-offs of <30%, 30%-59%, 60%-75% and >75% to suggest low, moderate, substantial and considerable heterogeneity, respectively [START_REF] Guyatt | GRADE guidelines: 7. Rating the quality of evidence-inconsistency[END_REF]. A p value < 0.10 was considered to indicate statistically significant heterogeneity using Cochran's Q test. Small study effects were assessed qualitatively using funnel plot asymmetry and quantitatively using Egger's regression test [START_REF] Egger | Meta-analysis: principles and procedures[END_REF]. All statistical analyses were performed with R-Studio software (Version 1.0.143).

Results

Vedolizumab

Of 794 unique studies identified using our search strategy, 17 studies were included [START_REF] Shelton | Efficacy of Vedolizumab as Induction Therapy in Refractory IBD Patients: A Multicenter Cohort[END_REF][START_REF] Eriksson | Long-term effectiveness of vedolizumab in inflammatory bowel disease: a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG)[END_REF][START_REF] Lenti | A real-world, long-term experience on effectiveness and safety of vedolizumab in adult patients with inflammatory bowel disease: The Cross Pennine study[END_REF][START_REF] Kopylov | Effectiveness and Safety of Vedolizumab in Anti-TNF-Naïve Patients With Inflammatory Bowel Disease-A Multicenter Retrospective European Study[END_REF][START_REF] Shmidt | Predictors and Management of Loss of Response to Vedolizumab in Inflammatory Bowel Disease[END_REF][START_REF] Christensen | Vedolizumab as Induction and Maintenance for Inflammatory Bowel Disease: 12-month Effectiveness and Safety[END_REF][START_REF] Samaan | Vedolizumab: early experience and mediumterm outcomes from two UK tertiary IBD centres[END_REF][START_REF] Allegretti | Predictors of Clinical Response and Remission at 1 Year Among a Multicenter Cohort of Patients with Inflammatory Bowel Disease Treated with Vedolizumab[END_REF][START_REF] Sands | Effects of vedolizumab induction therapy for patients with Crohn's disease in whom tumor necrosis factor antagonist treatment failed[END_REF][START_REF] Stallmach | Vedolizumab provides clinical benefit over 1 year in patients with active inflammatory bowel disease -a prospective multicenter observational study[END_REF][START_REF] Watanabe | Effects of vedolizumab in Japanese patients with Crohn's disease: a prospective, multicenter, randomized, placebo-controlled Phase 3 trial with exploratory analyses[END_REF][START_REF] Kotze | Real-world clinical, endoscopic and radiographic efficacy of vedolizumab for the treatment of inflammatory bowel disease[END_REF][START_REF] Biemans | Vedolizumab for Inflammatory Bowel Disease: Two-Year Results of the Initiative on Crohn and Colitis (ICC) Registry, A Nationwide Prospective Observational Cohort Study: ICC Registry -Vedolizumab[END_REF][START_REF] Pouillon | Vedolizumab Trough Levels and Histological Healing During Maintenance Therapy in Ulcerative Colitis[END_REF][START_REF] Meserve | Retrospective Analysis of Safety of Vedolizumab in Patients With Inflammatory Bowel Diseases[END_REF][START_REF] Colombel | The safety of vedolizumab for ulcerative colitis and Crohn's disease[END_REF]. In addition, we identified one abstract from conference proceedings, and two studies could be included after contacting the authors [START_REF] Amiot | Three-year Effectiveness and Safety of Vedolizumab Therapy for Inflammatory Bowel Disease: A Prospective Multi-Centre Cohort Study[END_REF][START_REF] Verstockt | Influence of Drug Exposure on Vedolizumab-Induced Endoscopic Remission in Anti-Tumour Necrosis Factor [TNF] Naïve and Anti-TNF Exposed IBD Patients[END_REF] and hence, included a total of 20 studies for quantitative synthesis (26) (Figure S1). The characteristics of these studies are summarized in Table 1. Three of these studies were randomized controlled trial [START_REF] Sands | Effects of vedolizumab induction therapy for patients with Crohn's disease in whom tumor necrosis factor antagonist treatment failed[END_REF][START_REF] Watanabe | Effects of vedolizumab in Japanese patients with Crohn's disease: a prospective, multicenter, randomized, placebo-controlled Phase 3 trial with exploratory analyses[END_REF][START_REF] Colombel | The safety of vedolizumab for ulcerative colitis and Crohn's disease[END_REF]. Among the 17 cohort studies, eight were prospective and two population-based. Two studies included only CD patients, one only UC patients. Finally, respectively 1890 and 4392 patients with combination therapy and monotherapy were included. Only five studies have reported the number of patients previously exposed / failed immunomodulator. The mean number of anti-TNF exposed patients was 80% (range, 0-98%). The range of quality assessment score for observational studies and post hoc analyses included in the meta-analyzed study was 6-8 (of maximum score of 8), indicating a high quality of the included studies (Table S1). The three RCTs included in the meta-analysis also were of relatively high quality (Table S2).

Clinical benefit

Sixteen studies including 2,053 CD patients and 1,260 UC were analyzed.

Respectively 933 and 2378 patients with combination therapy and monotherapy [START_REF] Shelton | Efficacy of Vedolizumab as Induction Therapy in Refractory IBD Patients: A Multicenter Cohort[END_REF][START_REF] Eriksson | Long-term effectiveness of vedolizumab in inflammatory bowel disease: a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG)[END_REF][START_REF] Lenti | A real-world, long-term experience on effectiveness and safety of vedolizumab in adult patients with inflammatory bowel disease: The Cross Pennine study[END_REF][START_REF] Kopylov | Effectiveness and Safety of Vedolizumab in Anti-TNF-Naïve Patients With Inflammatory Bowel Disease-A Multicenter Retrospective European Study[END_REF][START_REF] Shmidt | Predictors and Management of Loss of Response to Vedolizumab in Inflammatory Bowel Disease[END_REF][START_REF] Christensen | Vedolizumab as Induction and Maintenance for Inflammatory Bowel Disease: 12-month Effectiveness and Safety[END_REF][START_REF] Samaan | Vedolizumab: early experience and mediumterm outcomes from two UK tertiary IBD centres[END_REF][START_REF] Allegretti | Predictors of Clinical Response and Remission at 1 Year Among a Multicenter Cohort of Patients with Inflammatory Bowel Disease Treated with Vedolizumab[END_REF][START_REF] Sands | Effects of vedolizumab induction therapy for patients with Crohn's disease in whom tumor necrosis factor antagonist treatment failed[END_REF][START_REF] Parisi | Clinical response to vedolizumab in ibd patients is associated with the concomitant use of immunomodulators[END_REF][START_REF] Stallmach | Vedolizumab provides clinical benefit over 1 year in patients with active inflammatory bowel disease -a prospective multicenter observational study[END_REF][START_REF] Watanabe | Effects of vedolizumab in Japanese patients with Crohn's disease: a prospective, multicenter, randomized, placebo-controlled Phase 3 trial with exploratory analyses[END_REF][START_REF] Kotze | Real-world clinical, endoscopic and radiographic efficacy of vedolizumab for the treatment of inflammatory bowel disease[END_REF][START_REF] Biemans | Vedolizumab for Inflammatory Bowel Disease: Two-Year Results of the Initiative on Crohn and Colitis (ICC) Registry, A Nationwide Prospective Observational Cohort Study: ICC Registry -Vedolizumab[END_REF][START_REF] Amiot | Three-year Effectiveness and Safety of Vedolizumab Therapy for Inflammatory Bowel Disease: A Prospective Multi-Centre Cohort Study[END_REF][START_REF] Verstockt | Influence of Drug Exposure on Vedolizumab-Induced Endoscopic Remission in Anti-Tumour Necrosis Factor [TNF] Naïve and Anti-TNF Exposed IBD Patients[END_REF] were included. On meta-analysis, combination therapy was not associated with better clinical benefit as compared with monotherapy (OR 0.84; 95% CI 0.68-1.05) with low heterogeneity (I2 = 14%, Q test-pvalue=0.17) (Figure 1). No benefit in term of clinical remission (6 studies -OR 0.87; 95% CI, 0.57-1.31 -I2 = 29%, Q test- and maintenance (9 studies -OR 0.80; 95% CI, 0.64-1.01 -I2 = 5.2%, Q test-p=0.62) studies (Figures S7 andS8). Also similar results were observed in subgroups analysis including both cohorts studies (14 studies -OR 0.82; 95% CI, 0.67-1.02 -I2 = 4.5%, Q test-p=0.29) and randomized controlled trial (2 studies -OR 0.81; 95% CI, 0.18-3.55 -I2 = 77%, Q test-p=0.03), and both prospective (8 studies -OR 0.82; 95% CI, 0.58-1.15 -I2 = 35%, Q test-p=0.14) and retrospective studies (9 studies -OR 0.95; 95% CI, 0.72-1.25 -I2 = 0%, Q test-p=0.28). The symmetrical distribution of the studies on the funnel plot suggested that no publication bias was observed (p = 0.3372) (Figures S9).

Endoscopic remission

Three studies including a total of 589 patients were analyzed [START_REF] Kotze | Real-world clinical, endoscopic and radiographic efficacy of vedolizumab for the treatment of inflammatory bowel disease[END_REF][START_REF] Pouillon | Vedolizumab Trough Levels and Histological Healing During Maintenance Therapy in Ulcerative Colitis[END_REF][START_REF] Verstockt | Influence of Drug Exposure on Vedolizumab-Induced Endoscopic Remission in Anti-Tumour Necrosis Factor [TNF] Naïve and Anti-TNF Exposed IBD Patients[END_REF]. On metaanalysis combination therapy was not associated with better endoscopic outcome as compared with monotherapy (OR 1.13; 95% CI, 0.48-2.68) with no heterogeneity (I2 = 0%, Q test-p=0.96).

Safety

Four studies with 1,527 patients treated with vedolizumab in combination therapy, and 2,891 in monotherapy reported the numbers of adverse event [START_REF] Eriksson | Long-term effectiveness of vedolizumab in inflammatory bowel disease: a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG)[END_REF][START_REF] Lenti | A real-world, long-term experience on effectiveness and safety of vedolizumab in adult patients with inflammatory bowel disease: The Cross Pennine study[END_REF][START_REF] Meserve | Retrospective Analysis of Safety of Vedolizumab in Patients With Inflammatory Bowel Diseases[END_REF][START_REF] Colombel | The safety of vedolizumab for ulcerative colitis and Crohn's disease[END_REF].

On meta-analysis combination therapy was not associated with higher risk of adverse event (OR 1.17; 95% CI, 0.75-1.84) with no heterogeneity (I2 = 0%, Q test-p=0.110).

No increased risk of serious infections was observed (3 studies -OR 1.29; 95% CI, 0.75-2.21 -I2 = 0%, Q test-p=0.11).

Ustekinumab

Of 417 unique studies identified using our search strategy, 13 studies were included [START_REF] Miyazaki | Efficacies and Related Issues of Ustekinumab in Japanese Patients with Crohn's Disease: A Preliminary Study[END_REF][START_REF] Iborra | Real-world short-term effectiveness of ustekinumab in 305 patients with Crohn's disease: results from the ENEIDA registry[END_REF][START_REF] Biemans | Ustekinumab for Crohn's Disease: Results of the ICC Registry, a Nationwide Prospective Observational Cohort Study[END_REF][START_REF] Pugliese | Real-life effectiveness of ustekinumab in inflammatory bowel disease patients with concomitant psoriasis or psoriatic arthritis: An IG-IBD study[END_REF][START_REF] Liefferinckx | Long-term Clinical Effectiveness of Ustekinumab in Patients with Crohn's Disease Who Failed Biologic Therapies: A National Cohort Study[END_REF][START_REF] Battat | Association Between Ustekinumab Trough Concentrations and Clinical, Biomarker, and Endoscopic Outcomes in Patients With Crohn's Disease[END_REF][START_REF] Ma | Clinical, endoscopic and radiographic outcomes with ustekinumab in medically-refractory Crohn's disease: real world experience from a multicentre cohort[END_REF][START_REF] Feagan | Ustekinumab as Induction and Maintenance Therapy for Crohn's Disease[END_REF][START_REF] Khorrami | Ustekinumab for the Treatment of Refractory Crohn's Disease: The Spanish Experience in a Large Multicentre Open-label Cohort[END_REF][START_REF] Kopylov | Subcutaneous ustekinumab for the treatment of anti-TNF resistant Crohn's disease--the McGill experience[END_REF][START_REF] Sandborn | Ustekinumab induction and maintenance therapy in refractory Crohn's disease[END_REF][START_REF] Wils | Subcutaneous Ustekinumab Provides Clinical Benefit for Two-Thirds of Patients With Crohn's Disease Refractory to Anti-Tumor Necrosis Factor Agents[END_REF][START_REF] Sands | Ustekinumab as Induction and Maintenance Therapy for Ulcerative Colitis[END_REF]. Two studies could be included after contacting the authors (49-50) (Figure S10). Table 2 shows their main characteristics. Three of these studies were randomized controlled trial. Among the twelve cohort studies, all came from referral centers, four were prospective and eight multicenter. Only six studies have reported the number of patients previously exposed / failed immunomodulator, with a rate ranging from 60 to 100%. The mean number of anti-TNF exposed patients was 90% (range, 50-100%). The range of quality assessment score for observational studies and post hoc analyses included in the meta-analyzed study was 6-8, indicating a high quality of the included studies (Table S1). The thee RCTs included in the metaanalysis also were of relatively high quality (Table S2).

Clinical benefit

Fifteen studies including a total of 2,786 patients were included [START_REF] Miyazaki | Efficacies and Related Issues of Ustekinumab in Japanese Patients with Crohn's Disease: A Preliminary Study[END_REF][START_REF] Iborra | Real-world short-term effectiveness of ustekinumab in 305 patients with Crohn's disease: results from the ENEIDA registry[END_REF][START_REF] Biemans | Ustekinumab for Crohn's Disease: Results of the ICC Registry, a Nationwide Prospective Observational Cohort Study[END_REF][START_REF] Pugliese | Real-life effectiveness of ustekinumab in inflammatory bowel disease patients with concomitant psoriasis or psoriatic arthritis: An IG-IBD study[END_REF][START_REF] Liefferinckx | Long-term Clinical Effectiveness of Ustekinumab in Patients with Crohn's Disease Who Failed Biologic Therapies: A National Cohort Study[END_REF][START_REF] Battat | Association Between Ustekinumab Trough Concentrations and Clinical, Biomarker, and Endoscopic Outcomes in Patients With Crohn's Disease[END_REF][START_REF] Ma | Clinical, endoscopic and radiographic outcomes with ustekinumab in medically-refractory Crohn's disease: real world experience from a multicentre cohort[END_REF][START_REF] Feagan | Ustekinumab as Induction and Maintenance Therapy for Crohn's Disease[END_REF][START_REF] Khorrami | Ustekinumab for the Treatment of Refractory Crohn's Disease: The Spanish Experience in a Large Multicentre Open-label Cohort[END_REF][START_REF] Kopylov | Subcutaneous ustekinumab for the treatment of anti-TNF resistant Crohn's disease--the McGill experience[END_REF][START_REF] Sandborn | Ustekinumab induction and maintenance therapy in refractory Crohn's disease[END_REF][START_REF] Wils | Subcutaneous Ustekinumab Provides Clinical Benefit for Two-Thirds of Patients With Crohn's Disease Refractory to Anti-Tumor Necrosis Factor Agents[END_REF][START_REF] Sands | Ustekinumab as Induction and Maintenance Therapy for Ulcerative Colitis[END_REF][START_REF] Painchart | Ustekinumab Serum Trough Levels May Identify Suboptimal Responders to Ustekinumab in Crohn's Disease[END_REF][START_REF] Soufflet | Concentrations of Ustekinumab During Induction Therapy Associate With Remission in Patients With Crohn's Disease[END_REF]. Two studies were included with UC [START_REF] Iborra | Real-world short-term effectiveness of ustekinumab in 305 patients with Crohn's disease: results from the ENEIDA registry[END_REF][START_REF] Sandborn | Ustekinumab induction and maintenance therapy in refractory Crohn's disease[END_REF], and finally a total of respectively 2,458 and 328 CD and UC patients included. Overall, respectively 856 and 1,926 patients with combination therapy and monotherapy were included.

On meta-analysis, ustekinumab combination therapy was not associated with better clinical outcomes compared to ustekinumab monotherapy (OR 1.1; 95% CI 0.87-1.38) with low heterogeneity (I2 = 10.96%, Q test-p= 0.285) (Figure 2). The symmetrical distribution of the studies on the funnel plot suggested that no publication bias was observed (p = 0.3) (Figure S11

Endoscopic remission

Two studies including a total of 229 patients with CD were analyzed [START_REF] Pugliese | Real-life effectiveness of ustekinumab in inflammatory bowel disease patients with concomitant psoriasis or psoriatic arthritis: An IG-IBD study[END_REF][START_REF] Liefferinckx | Long-term Clinical Effectiveness of Ustekinumab in Patients with Crohn's Disease Who Failed Biologic Therapies: A National Cohort Study[END_REF]. On meta-analysis, combination therapy was not associated with better endoscopic outcome as compared with monotherapy (OR 0.58; 95% CI, 0.21-1.16) with moderate heterogeneity (I2 = 47%, Q test-p=0.167).

Safety

None of the studies had reported safety outcomes in patients with and without combination therapy with ustekinumab.

Discussion

This meta-analysis assesses the clinically relevant and controversial question of whether to combine an immunomodulator when initiating non anti-TNF biologics in patients with IBD. We observed that combination therapy with an immunomodulator was not associated with better clinical outcome whether in induction or maintenance, or better endoscopic outcome.

For many years, the only available biological therapies were anti-TNF agents. In CD and UC, there was general consensus that concomitant azathioprine or methotrexate with anti-TNFs is the most effective therapy and appropriate, except in special populations [START_REF] Colombel | Infliximab, Azathioprine, or Combination Therapy for Crohn's Disease[END_REF][START_REF] Feagan | Methotrexate in combination with infliximab is no more effective than infliximab alone in patients with Crohn's disease[END_REF](3)[START_REF] Kennedy | Predictors of anti-TNF treatment failure in anti-TNF-naive patients with active luminal Crohn's disease: a prospective, multicentre, cohort study[END_REF]. In naïve patients, the SONIC trial demonstrated the superiority of the combination of infliximab and azathioprine over monotherapy to obtain corticosteroid-free clinical remission in CD (1) and the SUCCESS trial (2) showed similar results in UC with 40% of corticosteroid-free remission at week 16 for patients receiving combination therapy, compared with 22% for patients receiving infliximab alone.

Data are more conflicting for patients previously exposed to immunomodulators. On the basis of a meta-analysis of randomized controlled trial, continued use of immunomodulator therapy after starting anti-TNF therapy is no more effective than anti-TNF monotherapy in inducing or maintaining response or remission [START_REF] Jones | Effects of Concomitant Immunomodulator Therapy on Efficacy and Safety of Anti-Tumor Necrosis Factor Therapy for Crohn's Disease: A Meta-analysis of Placebo-controlled Trials[END_REF]. Also, the benefit of combination therapy in non-infliximab anti-TNF is subject to debate. Recently, the DIAMOND study observed that the clinical efficacy of a combination of adalimumab and azathioprine did not differ from that of adalimumab monotherapy in CD naïve to both medications, despite a significant higher rate of endoscopic improvement in the combination group [START_REF] Matsumoto | Adalimumab Monotherapy and a Combination with Azathioprine for Crohn's Disease: A Prospective, Randomized Trial[END_REF].

Whereas an abundant literature is available for anti-TNF and combination therapy, there is a knowledge gap with regard to new biologics. No trials have specifically compared vedolizumab, or ustekinumab with immunomodulators vs monotherapy.

There also are limited data on the comparative efficacy of combination therapy over monotherapy from cohort studies. None of them had specifically addressed this question, whereas a significant proportion of the patients included in these studies were treated with immunomodulators. Finally, the few data available are conflicting.

Recently the AGA guidelines chose to rate the quality of evidence supporting vedolizumab, or ustekinumab with immunomodulator over vedolizumab, or ustekinumab monotherapy as low quality [START_REF] Singh | AGA Technical Review on the Management of Moderate to Severe Ulcerative Colitis[END_REF]. In the recent ECCO guidelines on therapeutics in CD, while the authors suggest against the combination of adalimumab and thiopurines over adalimumab alone, they did not state about combination therapy with non-anti-TNF biologics [START_REF] Torres | ECCO Guidelines on Therapeutics in Crohn's Disease: Medical Treatment[END_REF]. Through this meta-analysis, combination therapy was not associated with improved clinical and endoscopic outcome during both vedolizumab or ustekinumab therapies. Results were consistent in subgroup analysis, with the same results observed in induction and maintenance therapy, as in CD and UC, in randomized controlled trial and cohort studies as well as in prospective and retrospective studies.

Several controversial mechanisms have been proposed to explain the superiority of combination therapy over monotherapy. Combination therapy has a protective effect against anti-drug antibody development and lower trough levels, which were identified as one of the main drivers of primary non-response and loss of response during anti-TNF therapy (1,2). Post-hoc analyses of the SONIC trial suggested that the primary benefit of azathioprine was on pharmacokinetics of infliximab [START_REF] Colombel | Combination Therapy With Infliximab and Azathioprine Improves Infliximab Pharmacokinetic Features and Efficacy: A Post Hoc Analysis[END_REF], whereas the PANTS study showed that concomitant immunomodulator use in infliximab-treated patients was associated with higher remission at week 54 compared with no immunomodulator use, and this independently of drug concentration or immunogenicity status, suggesting that the addition of immunosuppression to anti-TNF therapy might have additional benefits [START_REF] Kennedy | Predictors of anti-TNF treatment failure in anti-TNF-naive patients with active luminal Crohn's disease: a prospective, multicentre, cohort study[END_REF].

As for anti-TNF, association between vedolizumab or ustekinumab concentration and clinical efficacy has been reported. However, unlike anti-TNF, prospective studies as well as post-hoc analysis of randomized controlled trial consistently reported a low immunogenicity. For vedolizumab, the LOVE study reported detectable drug antibodies in 1% to 4% of patients at different time points, that are transient in most cases without impacting VDZ serum concentrations [START_REF] Löwenberg | Vedolizumab Induces Endoscopic and Histologic Remission in Patients With Crohn's Disease[END_REF]. During the IM-UNITI long term follow-up, rates of antibodies to ustekinumab through week 156 was only 4.6%.

Also, all the prospective studies available to date have shown no impact of immunomodulator on the trough serum level of vedolizumab [START_REF] Verstockt | Influence of Drug Exposure on Vedolizumab-Induced Endoscopic Remission in Anti-Tumour Necrosis Factor [TNF] Naïve and Anti-TNF Exposed IBD Patients[END_REF][START_REF] Yarur | Vedolizumab Concentrations Are Associated with Long-Term Endoscopic Remission in Patients with Inflammatory Bowel Diseases[END_REF] or ustekinumab [START_REF] Adedokun | Ustekinumab Pharmacokinetics and Exposure Response in a Phase 3 Randomized Trial of Patients With Ulcerative Colitis: Ustekinumab PK and exposure-response in UC[END_REF][START_REF] Adedokun | Pharmacokinetics and Exposure Response Relationships of Ustekinumab in Patients With Crohn's Disease[END_REF]. The association of immunomodulator with biologics may also be deleterious.

Combination with anti TNF is associated with an increased risk of serious, opportunistic infections and lymphoma [START_REF] Lemaitre | Association Between Use of Thiopurines or Tumor Necrosis Factor Antagonists Alone or in Combination and Risk of Lymphoma in Patients With Inflammatory Bowel Disease[END_REF][START_REF] Kirchgesner | Risk of Serious and Opportunistic Infections Associated With Treatment of Inflammatory Bowel Diseases[END_REF]. On meta-analysis including 4 studies with 1,527 patients treated with vedolizumab in combination therapy, and 2,891 with vedolizumab monotherapy, combination therapy was not associated with an increased risk of adverse event. Similar data were not available for ustekinumab.

This study presents several limitations. Firstly, differences in the definition of clinical outcomes were observed, with studies reporting clinical remission and other clinical response, with their own definition. However, in subgroups analysis, we did not detect any benefit of combination therapy in studies evaluating clinical remission as in those evaluating clinical response. For endoscopic improvement, only two studies could be included on meta-analysis, thus limiting the interpretation of the results.

Secondly, our study does not address the question of the interest of combination therapy in patients who had been previously exposed to (and failed)

immunomodulator and those who had not because exposure rates were available in a too limited number of studies. Third, we must recognize that patients treated with combination therapy in the included studies could be more severe. This could influence our results. Also, were not able to evaluate separately the impact of thiopurines and methotrexate. Finally, we were unable to study the impact of immunomodulators on the biologics serum levels with the data currently available in the literature. On the other hand, this first meta-analysis evaluating the interest of combination therapy with the new biologics was not associated with significant heterogeneity across the analyses and no publication biases were observed. The results were consistent in all subgroups analysis performed, thus promoting the applicability of the results.

In conclusion, this meta-analysis found that overall the use of combination therapy in patients treated with vedolizumab or ustekinumab was not associated with a clinical benefit in comparison with the use of monotherapy. In subgroups analyses, consistent results were observed during induction and maintenance therapy for both drugs as well as for CD and UC for vedolizumab.

  Quality Assessment Two authors (CY and MF) independently extracted data on a standardized data collection form: (a) study characteristics: primary author, study period/year of publication, country of the study population, population source, number of patients, duration of follow-up; induction or maintenance study; (b) population characteristics: type of IBD; previous failure to immunomodulators or anti-TNFs; number of patients treated by combination as well as monotherapy, if available type of immunomodulator; (c) Outcome: clinical benefit / endoscopic improvement / safety:

p=0. 26 )

 26 , clinical response (5 studies -OR 0.60; 95% CI, 0.31-1.15 -I2 = 29%, Q test-p=0.18), global physician judgment (4 studies -OR 0.96; 95% CI, 0.70-1.31 -I2 = 19%, Q test-p=0.25) were observed (Figure S2, S3 and S4). Overall results were consistent in subgroup analysis with no difference in terms of clinical benefit in UC (7 studies -OR 0.92; 95% CI, 0.60-1.41 -I2 = 21%, Q test-p=0.23) or CD (9 studies -OR 0.84; 95% CI, 0.53-1.33 -I2 = 49%, Q test-p = 0.46) (Figures S5 and S6), and in both induction (11 studies -OR 0.84; 95% CI, 0.61-1.16 -I2 = 31%, Q test-p=0.06)

  ). No benefit in term of clinical remission (7 studies -OR 1.1; 95% CI, 0.76-1.57 -I2 = 0%, Q test-p=0.446), clinical response (5 studies -OR 1.1; 95% CI, 0.69-1.60 -I2 = 35%, Q test-p=0.212), global physician judgment (3 studies -OR 1.4; 95% CI, 0.40-4.54 -I2 = 58%, Q test-p=0.098) were observed (Figure S9, S10 and S11). Consistent results were observed in both induction (8 studies -OR 1.1; 95% CI, 0.81-1.49 -I2 = 26%, Q test-p=0.210) and maintenance studies (11 studies -OR 1.1; 95% CI, 0.89-1.47-I2 = 0%, Q test-p=0.712) (Figure S12 and S13).Also similar results were observed in subgroups analysis including both cohorts studies (12 studies -OR 1.0; 95% CI, 0.80-1.36 -I2 = 0%, Q test-p=0.58) and randomized controlled trial (3 studies -OR 1.30; 95% CI, 0.95-1.66 -I2 = 29%, Q test-p=0.24), and both prospective (7 studies -OR 1.20; 95% CI, 0.94-1.49 -I2 = 15%, Q test-p=0.353) and retrospective studies (8 studies -OR 1.10; 95% CI, 0.79-1.52 -I2 = 0%, Q test-p=0.36).

Figure 1 :

 1 Figure 1: Vedolizumab -Comparative Clinical Efficacy of Combination Therapy And Monotherapy In Inflammatory Bowel Diseases. OR, Odds Ratio ; CI, Confidence Interval.

Figure 2 :

 2 Figure 2: Ustekinumab -Comparative Clinical Efficacy of Combination Therapy And Monotherapy In Inflammatory Bowel Diseases. OR, Odds Ratio ; CI, Confidence Interval.

Table 1 : Vedolizumab -Characteristics of studies included in the analysis. RCT

 1 , Randomized Controlled trial ; W, Week ; HBI, Harvey-Bradshaw Index ; CDAI, Crohn's disease activity index ; CD, Crohn's disease ; UC, Ulcerative colitis ; PMS, Partial Mayo Score ; SCCAI, Simple Clinical Colitis Activity Index ; CS, Corticosteroids ; PGA, Physician global assessment.

	Study	Study design	Source	Country	Time period	Diseases (Crohn / UC), n	Medications Ustekinumab Ustekinumab ab combo, n mono, n	Outcome (definition)	Timepoint
	Miyazaki et al. 2020	Monocenter retrospective cohort	Referral center	Japan	2017-2018	47 / 0	18	29	Clinical remission (CDAI < 150 points)	W8 / W24
	Iborra et al. 2019	Multicenter retrospective cohort	Referral center	Spain, ENEIDA	/	305 / 0	122	183	Clinical remission (HBI score ≤ 4 points)	W14
	Biemans et al. 2020	Multicenter prospective cohort	Referral center	Netherland, ICC registry	2016-2019	221 / 0	44	177	CS free clinical remission (HBI ≤ 4 points)	W12 / W 24 / W52
	Pugliese et al. 2019	Multicenter, retrospective cohort	Referral center	Italy	2012-2017	64 / 6	11	59	Clinical remission (HBI ≤ 4 or PMS ≤ 2 with no subscore > 1)	Last follow up
	Liefferinckx et al. 2019	Multicenter retrospective cohort	Referral center	Belgium	2016-2017	152 / 0	25	127	Clinical remission (HBI ≤4 points)	W52
	Battat et al. 2017	Multicenter prospective cohort	Referral center	Canada, Montreal	2014-2015	62 / 0	16	46	Clinical response (reduction HBI ≥ 3) more or SES-CD ≤2) Endoscopic response (SES-CD reduced by 50% or	W 26
									Clinical response (improvement in disease symptoms
									by either PGA or decrease in HBI ≥3 points and
	Ma et al. 2017	Multicenter retrospective cohort	Referral center	Canada	2011-2016	167 / 0	73	94	complete tapering of steroids). Endoscopic response: improvement in mucosal	W26
									inflammation compared to baseline with at minimum,
									resolution of deep ulcerations
	Feagan et al. 2016	RCT	Referral center	International	2011-2015	931 / 0	320	607	Clinical response (decrease from baseline in CDAI ≥ 100 points or a total CDAI score ≤ 100), Clinical remission (CDAI <150 points)	W6 W44
	Khorrami et al. 2016	Multicenter Retrospective cohort	Referral center	Spain	2010-2014	116 / 0	42	74	Clinical benefit defined as clinical remission (HBI ≤4), or response (decrease in HBI ≥ 3)	Between W8 and W12
	Kopylov et al. 2014	Monocenter retrospective cohort	Referral center	Canada, Montreal	2011-2013	40 / 0	4	36	Clinical response (improvement in the patient's symptoms coupled with the decision to continue ustekinumab treatment)	End of follow up

Table 2 : Ustekinumab -Characteristics of studies included in the analysis

 2

. RCT, Randomized Controlled trial ; W, Week ; HBI, Harvey-Bradshaw Index ; CDAI, Crohn's disease activity index ; CD, Crohn's disease ; UC, Ulcerative colitis ; PMS, Partial Mayo Score ; CS, Corticosteroids ; PGA : Physician Global assessment ; SES-CD, Simple endoscopic score-Crohn's disease.

Research grants from AbbVie and Janssen MF : Abbvie, Ferring, MSD, Janssen, Takeda,