Weight Gain and Metabolic Control in Newly Insulin-treated Patients With Type 2 Diabetes With Different Insulin Regimens

Abstract

ABSTRACT OBJECTIVE Weight gain with insulin therapy is a well-known side effect of the pharmacologic management of type 2 diabetes, but appears to occur less frequently when an insulin analogue is used.The aim of the study was to determine differences in weight gain and insulin requirement in patients on different insulin therapy regimens. METHODS We retrospectively evaluated 154 patients with type 2 diabetes newly treated with insulin due to failure of secondary sulfonylurea treatment. The indication was secondary sulfonylurea failure with A1C > 7.5% (2 measurements). All patients had participated in a 5-day diabetes education program and were permitted to select their own insulin regimen from the following choices: 1) conventional insulin therapy (an insulin mix containing 25 or 30% regular insulin or insulin lispro and 70 or 75% NPH insulin injected twice daily); 2) the combination of insulin (insulin mix or NPH insulin, injected once daily) and sulfonylurea (glimepiride or gliclazide); or 3) prandial insulin therapy consisting of regular or lispro insulin as short-acting insulin 3 times daily and bedtime NPH insulin. The following parameters were compared at the start of insulin therapy and after 12 months: weight, body mass index (BMI), glycosylated hemoglobin (A1C), cholesterol, triglycerides (TG), insulin requirement and the influence of metformin on the insulin requirement. In addition, we measured basal C-peptide at the start of insulin therapy and evaluated the incidence of hypoglycemia during the observation period. RESULTS Weight gain was similar in the 3 groups: 2.6%, 2.7% and 2.5%, respectively; mean weight gain was 2.1 kg (2.6%). A1C decreased by − 2.2% (23%), -1.8% (19%) and − 1.8% (18%), respectively. The group who received the insulin and sulfonylurea combination required a much lower initial insulin dose than the other groups. The increase in the required insulin dose over 12 months was similar in the 3 groups: 8% in patients receiving insulin and sulfonylurea, 10% in those receiving the conventional insulin regimen and 8% in the group receiving prandial insulin substitution. Mean total cholesterol levels did not decrease significantly from baseline in the 3 groups (decrease: -4%, -3% and − 5%, respectively), and there were no significant difference between the groups. TG levels decreased to a similar extent: 20, 18 and 17%, respectively.The patients in each group who also took metformin experienced a 22% lower increase in their mean insulin requirement than did those who used insulin without metformin. CONCLUSION Weight gain in insulin-treated patients with type 2 diabetes was similar with different insulin regimens; the mean increase at 1 year was 2.6%. The 3 patient groups experienced similar metabolic control and similar increases in insulin requirements. The additional intake of metformin was associated with a 22% lower increase in the required insulin dose.