Factors determining first influenza vaccination among individuals with type 2 diabetes in the CONSTANCES cohort by age group (younger than 65 years or 65 and older)

Vaccine coverage against influenza is suboptimal among people with diabetes. Our principal objective was to study and compare the factors related to a first influenza vaccination in individuals with type 2 diabetes according to age group (<65 years and >= 65 years) and then to compare the older age group with diabetes to the general population of that age. This is a descriptive cross-sectional study within the French Constances cohort. The study populations were composed of people with type 2 diabetes and individuals without diabetes 65 years and older. Our variable of interest was the first reimbursement for a vaccine against influenza over the period from 2009 to 2019. We identified 2540 cohort members with type 2 diabetes (<65 years n = 1583; >= 65 years n = 957). The population without diabetes (>= 65 years) comprised 18,364 individuals. The factors related to the first influenza vaccination differed significantly between the persons with diabetes younger than 65 years and those aged at least 65 years: age (OR = 1.01/OR = 0.89-P-interaction<0.001), poor perceived health (OR = 1.24/OR = 0.79-P-interaction = 0.048), and indicators of diabetes treatment quality [at least 2 hbA1c assays/year (OR = 1.91/0 R = 0.90-P-interaction<0.001), and blood pressure < 140/90 (OR = 1.24/OR = 0.90-P-interaction = 0.059)]. The only factor related to first influenza vaccination significantly different between individuals aged at least 65 years with and without diabetes was age (OR = 0.83/OR = 1.05-P-interaction<0.001). This study shows that trials are now needed to test the effectiveness of age- and sex-specific messages to increase influenza vaccination coverage among people with diabetes.