Marc Diedisheim

Etienne Dancoisne

Jean-François Gautier

Etienne Larger

Emmanuel Cosson

Bruno Fève

Philippe Chanson

Sébastien Czernichow

Sopio Tatulashvili

Marie-Laure Raffin-Sanson

Kankoé Sallah

Muriel Bourgeon

Christiane Ajzenberg

Agnès Hartemann

Christel Daniel

Thomas Moreau

Ronan Roussel

Dr Louis Potier
email: louis.potier@aphp.fr

Response Letter to the Editor from Woolcott & Castilla-Bancayán:Diabetes Increases Severe COVID-19 Outcomes Primarily in Younger Adults

Keywords: diabetes, covid-19, mortality, age

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

We thank Drs Woolcott and Castilla-Bancayán [START_REF] Woolcott | Letter to the Editor: "Diabetes increases severe COVID-19 outcomes primarily in younger adults: Age and diabetes in COVID-19 severity[END_REF] for their interest in our article [START_REF] Diedisheim | Diabetes increases severe COVID-19 outcomes primarily in younger adults Age and diabetes in COVID-19 severity[END_REF].

They suggest potential explanations to the differences with their own study [START_REF] Woolcott | The effect of age on the association between diabetes and mortality in adult patients with COVID-19 in Mexico[END_REF].

We agree that exclusion of a large number of patients may undermine the power to detect significant differences. However, given the influence of obesity on severe forms of COVID-19 (4) we decided against imputing missing values or removing body mass index (BMI) from the multivariate adjusted model. For information, we conducted an analysis including patients without available BMI, therefore not using it in the multivariate adjusted model, and found that mortality was significantly different between patients with or without Concerning the 90-day period, a minority of deaths occurred between 28 and 90 days : 16% in patients with diabetes and 14% in those without diabetes (p-value = 0.56).

Analyzing the results with a restricted 28-day follow-up criterion did not modify our conclusions significantly.

Besides, although we agree that ethnic differences might influence analysis, such information was not available in our database. Another possible explanation could arise from the difference in mortality rate between the two cohorts. In the Mexico cohort, death occurred in 47% (28,254/60,469) and 36% (43,613/120,875) of patients with or without diabetes respectively (3). In our cohort, these rates were 26% (637/2,549) and 22% (831/3,855) for patients with or without diabetes respectively. This difference in absolute mortality rate might influence the relative weight of diabetes, and could related to many factors: different indications for hospitalizations, diabetes with difference in duration, treatments, complications, glycated hemoglobin, etc. To conclude, we agree that evidence tends to suggest that the risk of severe COVID-19 forms associated with diabetes decreases with age but also acknowledge that it is difficult to ascertain a precise age threshold.

  diabetes up to 70 years: <50 HR 2.06 [1.36-3.14] (p-value <0.001), 50-60 HR 1.35 [1.01-1.82] (p-value 0.04), and 60-70 HR 1.23 [1.00-1.52] (p-value 0.049), but not between 70-80 (HR 1.14 [0.96-1.35], p-value 0.13) nor > 80 (HR 0.91 [0.80-1.04], p-value 0.17).