Characteristics of undiagnosed diabetes in community-dwelling French elderly: the 3C study.

We aimed to assess clinical and socio-demographic characteristics of undiagnosed diabetes, including glucose control, in French community-living elderly people. Diagnosed and undiagnosed diabetes, impaired fasting glucose (IFG) and characteristics of subjects were assessed by interview, clinical examination and fasting blood glucose measures at the baseline visit of the Three-City (3C) study including 9294 people over 65 in three urban areas in France. In the Bordeaux sample, HbA1c was measured in diabetic and IFG subjects and in a sub-sample of non-diabetic subjects. The proportion of diagnosed diabetes, undiagnosed diabetes and IFG was, respectively, 8.2%, 1.4% and 3.6%. Diabetic and IFG subjects were more likely to be men, to suffer from hypertension and to be overweight. They were less likely to have a high income and more likely to have a lower educational level. These factors were unrelated to knowledge of diabetic status. In the Bordeaux sub-sample, 19.6% of the diagnosed diabetic subjects and 16.1% of those undiagnosed had an HbA1c greater than 8%. Prevalence of ischemic heart disease was more common in diagnosed than in undiagnosed diabetic subjects (P=.021). A significant number of undiagnosed elderly had poor glucose control suggesting a potential benefit for diabetes screening in the elderly.