A comparison of biphasic insulin aspart and insulin glargine administered with oral antidiabetic drugs in type 2 diabetes mellitus - a systematic review and meta-analysis

ObjectiveIt is uncertain whether the addition of biphasic insulin analogues to oral antidiabetic drugs (OADs) is as effective and safe as basal insulin in patients with type 2 diabetes mellitus (T2DM). We performed a systematic review to compare glycaemic control and selected clinical outcomes in T2DM patients inadequately controlled with OADs whose treatment was intensified by adding biphasic insulin aspart (BIAsp 30) or insulin glargine (IGlar). MethodsThe analysis included randomised controlled trials (RCTs) identified by a systematic literature search in medical databases (MEDLINE, EMBASE, The Cochrane Library and other sources) up to March 2013. Studies met the inclusion criteria if they compared BIAsp 30 vs. IGlar added to at least one OAD in T2DM patients. Trials applying different OADs in both treatment arms were also included. Results were presented as weighted mean difference (WMD) or odds ratio (OR) with a 95% confidence interval (CI). ResultsFive trials, including a total number of 1758 patients followed up from 24 to 28weeks, were identified. Quantitative synthesis demonstrated that BIAsp 30 reduced HbA1c level more efficiently than IGlar [5 RCTs; WMD (95% CI): -0.21% (-0.35%, -0.08%)]. Differences were observed in favour of BIAsp for lower mean prandial glucose increment [3RCTs; WMD (95% CI): -14.70mg/dl (-20.09, -9.31)]; no difference was observed for fasting plasma glucose [3 RCTs; WMD (95% CI): 7.09mg/dl (-15.76, 29.94)]. We found no evidence for higher risk of overall [2 RCTs; 63% vs. 51%; OR=1.77 (0.91; 3.44)] and severe hypoglycaemic episodes [4 RCTs; 0.98% vs. 1.12%; OR (95% CI)=0.88 (0.31, 2.53)] in the BIAsp 30 group as compared with IGlar group. Twice-daily administration of BIAsp 30 resulted in larger weight gain [2 RCTs; WMD (95% CI)=1.78kg (1.04; 2.52)]. ConclusionsBIAsp 30 added to OAD therapy results in a better glycaemic control as compared with IGlar in T2DM patients. BIAsp 30 use is associated with slightly larger weight gain but no rise in risk of severe hypoglycaemic episodes.