Insulin-induced weight gain and cardiovascular events in patients with type 2 diabetes. A report from the DIGAMI 2 study

Aim: We investigated whether insulin treatment-induced weight gain was accompanied by increased cardiovascular (CV) mortality and morbidity in the second Diabetes Insulin Glucose in Acute Myocardial Infarction (DIGAMI 2) study. Methods: We studied the 865 patients who survived during 12 months without any change in their glucose-lowering (GL) therapy. They were divided into four subgroups according to GL treatment: group I, no pharmacological GL treatment (n = 99); group II, oral hypoglycaemic agents (n = 250); group III, new insulin treatment (n = 245) and group IV, insulin before inclusion continued during the first year of follow up (n = 271). Results: Patients who started on insulin (group III) experienced an average body weight increase of 2.3 (1.5-3.2) kg during the first year of treatment, whereas weight remained unchanged in groups I, II and IV. The incidence of non-fatal reinfarction was higher in group III compared with the other groups (hazard ratio (HR) 2.5, p = 0.011) and CV mortality was higher in group IV (HR 2.4, p = 0.003). When the subjects were grouped in quartiles according to maximal body weight increase, those in the lowest quartile experienced the highest CV mortality. Each kilogram increase in weight reduced the risk for CV death with 6%. The incidence of reinfarction did not differ between quartiles. Conclusions: Initiation of insulin treatment after myocardial infarction was associated with a significant increase in weight and incidence of reinfarction. The increase in weight did, however, not explain the increased rate of reinfarction.