Factors Associated With Weight Gain in People With Type 2 Diabetes Starting on Insulin

OBJECTIVE Moderate weight gain is usual after starting insulin therapy. The identification and quantification of factors associated with weight gain may help target strategies for avoidance of weight gain. RESEARCH DESIGN AND METHODS The noninterventional CREDIT (Cardiovascular Risk Evaluation in people with type 2 Diabetes on Insulin Therapy) study included data from people with type 2 diabetes starting any insulin in 314 centers, in 12 countries. From a number of predefined candidate explanatory variables, analyses identified factors associated with weight gain 1 year after starting insulin treatment, after adjusting for investigational site as a random factor. A multivariable backward regression analysis selected a subset of these factors associated with weight gain. RESULTS We studied the 2,179 people with data for body weight change at 1 year and for potential predictive factors. The mean weight gain was 1.78 kg, and 24% gained >= 5.0 kg. Baseline factors associated with weight gain were BMI, A1C, insulin regimen, insulin dose, other glucose-lowering therapies, and hypertension; at 1 year, additional factors were A1C, insulin regimen, insulin dose, and use of other glucose-lowering therapies. In multivariable analysis, weight gain at 1 year was associated with a higher A1C at baseline, a higher insulin dose at baseline and at 1 year, and a lower baseline BMI. CONCLUSIONS By the time insulin was started, a high baseline A1C and insulin dose requirements were independently associated with greater weight gain, as was lower baseline BMI. Insulin regimen per se was not a predictive factor.