Evaluation of the weight-increasing effects of biphasic analog and regular NPH insulin mixtures in patients with Type 2 diabetes mellitus.

Background: Weight gain is a significant problem in diabetic patients in terms of worsening glycemic control, increasing diabetic and cardiovascular morbidity and mortality, and contributing to social and psychological problems. In the present study, we evaluated the effects of a biphasic analog and regular NPH insulin mixtures on weight gain in patients with Type 2 diabetes mellitus (T2DM) over 1 year.

Methods: Group I consisted of 71 patients (29 men and 42 women) being treated with analog mixtures (insulin lispro 75/25 mix and biphasic insulin aspart 70/30 mix) twice daily; Group II consisted of 69 patients (23 men and 46 women) being treated with a regular insulin mixture (70/30) twice daily. Starting weight, body mass index, HbA1c, and hypoglycemic episodes were evaluated after 6 and 12 months.

Results: Weight gain in Group I at 6 and 12 months was 1.41 ± 2.70 and 2.08 ± 3.74 kg, respectively. In Group II, weight gain at 6 and 12 months was 1.5 ± 3.0 and 2.29 ± 3.85 kg, respectively. Intragroup comparisons indicated that, for both groups, weight gain at 6 and 12 months differed significantly from the starting weight. However, no significant differences in weight gain were found between the two groups (P > 0.05).

Conclusions: The weight-increasing effects of an analog mixture of insulin and the NPH regular mixture of insulin appear to be similar. This should be taken into account when determining the type of insulin to use in treating T2DM patients.