Combination-therapy with bedtime nph insulin and sulphonylureas gives similar glycaemic control but lower weight gain than insulin twice daily in patients with type 2 diabetes

Abstract

Background: To study the effect on body weight and glycaemic control of two insulin treatment regimens in patients with Type 2 diabetes and moderate failure to oral hypoglycaemic agents.

Methods: Sixteen patients treated with oral hypoglycaemic agents (6 men and 10 women) were included in this open-label, randomized, parallel group study. Their age was 62 +/- 2 (mean +/- SEM) years (range 44-79 years), body weight 71.3 +/- 2.9 kg, body mass index (BMI) 24.6 +/- 0.8 kg/m(2). The patients were switched to insulin treatment with bedtime NPH insulin combined with daytime sulphonylurea (combination group) or twice daily injections of a premixed combination of regular human and NPH insulin (insulin twice daily group) with measurements as given below before and after 12 and 24 weeks of treatment.

Results: HbA(1c) was lowered from 8.3 +/- 0.3% to 7.0 +/- 0.2% in the insulin twice daily group (p<0.05) and from 8.3 +/- 0.3% to 6.8 +/- 0.5% in the combination group (p<0.03; ns between treatment groups). Body weight increased from 71.7 +/- 4.0 kg to 77.6 +/- 4.4 kg in the insulin twice daily group (p<0.001) and from 70.8 +/- 4.6 kg to 72.7 +/- 5.1 kg in the combination group (ns; p<0.02 between groups). The dose of insulin at 24 weeks in the insulin twice daily group was 45.8 +/- 4.2 U and 29.4 +/- 5.4 U in the combination group (p=0.03). Combination treatment reduced fasting and stimulated C-peptide levels.

Conclusions: Both treatments improved glycaemic control to the same extent but the combination of bedtime NPH insulin and daytime sulphonylurea gave a very small increase of body weight over a 6 months period. We conclude that combination therapy is an attractive alternative when starting insulin treatment in patients with Type 2 diabetes as this is a critical period for weight gain in such patients.