Risk for nocturnal hypoglycemia with biphasic insulin aspart 30 compared with biphasic human insulin 30 in adults with type 2 diabetes mellitus: a meta-analysis.

BACKGROUND: Insulin is recommended as a second-line treatment after diet and metformin fail to reach and/or maintain glycemic targets considered to minimize the risk for long-term diabetic complications. Hypoglycemia and the fear of developing hypoglyce-mia, however, remain substantial barriers to the initiation and optimal use of insulin.
OBJECTIVE: The aim of this study was to compare biphasic insulin aspart 30 (BIAsp 30) with biphasic human insulin 30 (BHI 30) with respect to glycemic control and the risk for hypoglycemia using a meta-analysis of clinical trials comparing these insulins in patients with type 2 diabetes mellitus (T2DM).
METHODS: We included all published and unpublished, randomized, controlled trials in adult patients with T2DM (treatment duration > or = 12 weeks) for which individual patient data were available. All clinical databases and local trial registries of Novo Nordisk A/S (Soeborg, Denmark) were searched to identify clinical trials comparing the 2 products. The predefined primary end point of the study was the overall rate of nocturnal hypoglyce-mia (major, minor, and symptoms-only hypoglycemia occurring from 12:00-6:00 AM). Hypoglycemia was analyzed using a negative binomial distribution model, accounting for exposure time. Glycemic end points were analyzed at 12 to 16 weeks of treatment using ANCOVA, adjusting for baseline. Secondary safety end points were the rates of major hypoglycemia (hypoglycemia requiring third-party assistance), minor hypoglycemia (symptoms confirmed by plasma glucose [PG] <3.1 mmol/L), daytime hypoglycemia (major, minor, and symptoms-only hypoglycemia occurring from 6:01 AM-11:59 PM), overall hypoglycemia (the sum of all major, minor, and symptoms-only episodes), and change in weight from baseline to 12 to 16 weeks of treatment. Secondary efficacy end points were changes in glycosylated hemoglobin (HbA(1c)), fasting PG (FPG), postprandial PG increment (averaged over breakfast, lunch, and dinner), and insulin dose.
RESULTS: Nine randomized, parallel or crossover trials were included (N = 1674; male sex, 57%; mean [SD] age, 61.0 [10.6] years; body mass index, 26.7 [4.6] kg/m(2); HbA(1c), 8.1% [1.4%]; duration of diabetes, 10.9 [7.9] years). Rates of overall hypoglycemia were not significantly different (rate ratio [RR] = 1.08; 95% CI, 0.94-1.24; P = NS) between treatments. BIAsp 30 had a 50% lower rate of nocturnal hypoglycemia than BHI 30 (RR = 0.50; 95% CI, 0.38-0.67; P < 0.01), whereas the rate of daytime hypoglycemia was 24% lower for BHI 30 (RR = 1.24; 95% CI, 1.08-1.43; P < 0.01). The likelihood of major hypo-glycemia was significantly lower with BIAsp 30 compared with BHI 30 (odds ratio = 0.45; 95% CI, 0.22-0.93; P < 0.05). BIAsp 30 was associated with reduced PPG increment (averaged over breakfast, lunch and dinner) compared with BHI 30 (treatment difference, -0.31; 95% CI, -0.49 to -0.07; P < 0.01). There was a significantly larger reduction in FPG associated with BHI 30 (treatment difference, 0.63; 95% CI, 0.31-0.95; P < 0.01). However, no significant treatment difference was found for HbA(1c) (treatment difference, 0.04; 95% CI, -0.02 to 0.10; P = NS).
CONCLUSION: This meta-analysis found BIAsp 30 to be associated with a significantly lower rate of nocturnal and major hypoglycemia, but a significantly increased risk for daytime hypoglycemia, compared with BHI 30 at a similar level of HbA(1c) in patients with T2DM.