Association between BMI measured within a year after diagnosis of type 2 diabetes and mortality.

OBJECTIVE To describe the association of BMI with mortality in patients diagnosed with type 2 diabetes. RESEARCH DESIGN AND METHODS Using records of 106,640 patients in Scotland, we investigated the association between BMI recorded around the diagnosis of type 2 diabetes mellitus (T2DM) and mortality using Cox proportional hazards regression adjusted for age and smoking status, with BMI 25 to 30 kg/m2 by 24% (15–35%) in men and 23% (14–32%) in women, but was lower below this threshold. The results were similar after further adjustment for HbA1c, year of diagnosis, lipids, blood pressure, and socioeconomic status. CONCLUSIONS Patients categorized as normal weight or obese with T2DM within a year of diagnosis of T2DM exhibit variably higher mortality outcomes compared with the overweight group, confirming a U-shaped association of BMI with mortality. Whether weight loss interventions reduce mortality in all T2DM patients requires study. Compared with normal weight, obesity is associated with increased all-cause mortality in the general population, as well as increased cardiovascular and cancer mortality (excluding smoking-related cancers) (1–3). However, the findings in patients with type 2 diabetes mellitus (T2DM) have been variable, with some studies reporting an increase in all-cause mortality with increasing body mass (4–6), but many studies finding no relationship (7–10) or a decrease in mortality with higher BMI (11). This may be due to limited power, as those studies describing no association all included <1,000 individuals (7–10) and limitations of the analytical approaches. In the general population, the relationship between BMI and mortality is U-shaped (1) with excess mortality seen at BMI