Clinical effectiveness of biphasic insulin aspart 30:70 versus biphasic human insulin 30 in UK general clinical practice: a retrospective database study.

BACKGROUND

Premixed, or biphasic, insulins containing varying proportions of rapid- and intermediate-acting insulin components have been developed to limit the number of daily injections for patients who require both prandial and basal insulin injections.

OBJECTIVES

This study was conducted to determine whether there were differences in glycosylated hemoglobin (HbA(1c)), weight change, hypoglycemia occurrence, and treatment discontinuation between patients treated with biphasic insulin aspart 30 (BIAsp-30) or biphasic human insulin 30 (BHI-30) in UK general practice.

METHODS

Data were from >350 general practices from the United Kingdom. Patients were stratified by treatment regimen, diabetes type, and insulin status (naive or experienced). Changes in HbA(1c) and weight were compared from baseline (the date of the first prescription for either insulin) through 180 days of follow-up using ANCOVA. Hypoglycemia incidence rate ratios were compared, and the adjusted likelihood of hypoglycemia was evaluated by logistic regression. Rates of treatment discontinuation were compared using the Cox proportional hazards model.

RESULTS

The study included data from 7720 patients, of whom 1333 (17.3%) had type 1 diabetes and 4457 (57.7%) were male. Patients' mean (SD) age was 57.9 (19.8) years, and their mean body mass index was 29.5 (6.2) kg/m(2). The difference in HbA(1c) reduction was significant for BIAsp-30 compared with BHI-30 in insulin-naive patients with type 1 diabetes (0.57%; P = 0.045), insulin-naive patients with type 2 diabetes (-0.17%; P = 0.003), and insulin-experienced patients with type 2 diabetes (-0.23%; P = 0.007). The difference between insulins was not significant in insulin-experienced patients with type 1 diabetes. Five hundred ninety-four patients (7.7%) experienced at least one hypoglycemic event. The incidence rate ratio for reported hypoglycemia was significantly lower with BIAsp-30 compared with BHI-30 in insulin-naive patients with type 2 diabetes (0.74; 95% CI, 0.62-0.89; P = 0.001); the difference between insulins was not significant in the other groups. The adjusted hazard ratio for treatment discontinuation was significant for BIAsp-30 versus BHI-30 in insulin-experienced patients with type 2 diabetes (0.693; 95% CI, 0.543-0.884; P = 0.003), whereas the hazard ratios for the other groups did not reach statistical significance. There were no significant differences in weight change between BIAsp-30 and BHI-30 in any of the groups.

CONCLUSIONS

In this analysis, BIAsp-30 was associated with improved glycemic control (HbA(1c)) compared with BHI-30 in insulin-naive patients with type 1 or type 2 diabetes and insulin-experienced patients with type 2 diabetes. BIAsp-30 was associated with reduced hypoglycemia in insulin-naive patients with type 2 diabetes and lower rates of treatment discontinuation in insulin-experienced patients with type 2 diabetes. Cambridgeshire Research Ethics Committee: REC 08/H0305/47.