Changes in body mass index following newly diagnosed type 2 diabetes and risk of cardiovascular mortality: a cohort study of 8486 primary-care patients

Abstract

Aims: Elevated body mass index (BMI) is associated with an increased risk of type 2 diabetes and cardiovascular disease (CVD). This study explored the association between BMI changes in the first 18 months of newly diagnosed type 2 diabetes and the risk of long-term CVD mortality.

Methods: A total of 8486 patients with newly diagnosed type 2 diabetes and no previous history of CVD or cancer were identified from 84 primary-care centres in Sweden. During the first year after diagnosis, patients were grouped according to BMI change: 'Increase', or ≥+1 BMI unit; 'unchanged', or between +1 and-1 BMI unit; and 'decrease', or ≤-1 BMI unit. Associations between BMI change and CVD mortality, defined as death from stroke, myocardial infarction or sudden death, were estimated using adjusted Cox proportional hazards models (NCT 01121315).

Results: Baseline mean age was 60.0 years and mean BMI was 30.2kg/m(2). Patients were followed for up to 9 years (median: 4.6 years). During the first 18 months, 53.4% had no change in their BMI, while 32.2% decreased and 14.4% increased. Compared with patients with unchanged BMI, those with an increased BMI had higher risks of CVD mortality (hazard ratio: 1.63, 95% CI: 1.11-2.39) and all-cause mortality (1.33, 1.01-1.76). BMI decreases had no association with these risks compared with unchanged BMI: 1.06 (0.76-1.48) and 1.06 (0.85-1.33), respectively.

Conclusion: Increased BMI within the first 18 months of type 2 diabetes diagnosis was associated with an increased long-term risk of CVD mortality. However, BMI decrease did not lower the long-term risk of mortality.

Keywords: Cardiovascular disease mortality; Diabète de type 2; Epidemiology; La mortalité cardiovasculaire; Le contrôle du poids; Type 2 diabetes; Weight control; Épidémiologie.