Sustained-release versus immediate-release glipizide for treatment of type 2 diabetes mellitus in chinese patients: A randomized, double-blind, double-dummy, parallel-group, 12-week clinical study

BACKGROUND: Few data exist that have compared sulfonylurea formulations in differing ethnic populations. Most studies of sulfonylureas have been performed in white patients with type 2 diabetes mellitus. OBJECTIVE: The aim of this study was to compare the efficacy and tolerability of a sustained-release glipizide (GSR) formulation with those of immediate-release glipizide (GIR) in Chinese patients with type 2 diabetes mellitus. METHODS: This randomized, double-blind, double-dummy, placebo-controlled, parallel-group, clinical study enrolled adult patients with type 2 diabetes mellitus who were already being treated with diet and a sulfonylurea. Patients were randomized to receive either GSR 10 mg PO QD or GIR 5 mg PO BID for 12 weeks. Because these 2 formulations differed in appearance, each patient also received placebo resembling the alternate formulation, to be received at the alternate frequency. Drugs dispensed but not used were returned to the investigators and counted to monitor compliance with the protocol. For efficacy assessment, fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA(1c)) were measured before and after treatment. Tolerability was measured by adverse events (AEs), which were evaluated by the attending physician during each clinical visit. RESULTS: Of the 57 patients (37 men, 20 women) enrolled in the study, 41 completed it. All were Han Chinese of Taiwanese origin, and had the following characteristics: age range, 33 to 69 years; mean (SE) height, 161.99 (9.42) cm; and mean (SE) body mass index, 25.21 (3.43) kg/m2. An intent-to-treat analysis found that the mean (SE) changes from baseline in FPG (-30.00 [10.67] vs -25.96 [11.15] mg/dL) and in HbA(1c) (-0.08% [0.24%] vs +0.14% [0.22%]) during the 12-week period of the study were not significantly different between the 2 formulations. For patients in the per-protocol analysis, mean (SE) changes from baseline in FPG (-30.00 [10.67] vs -16.52 [7.79] mg/dL) and HbA(1c) (-0.08% [0.24%] vs +0.11% [0.25%]) were also not significantly different. The most frequently reported AEs were urinary abnormality (22.2%) and tachycardia (6.7%) for the GSR group and GIR group, respectively. No serious drug-related AEs were observed in either group. CONCLUSION: In this small study, treatment with oral GSR (10 mg QD) was not significantly different from that of treatment with GIR (5 mg BID) with respect to short-term (12 weeks) FPG and HbA(1c) reductions in these ethnic Chinese adults with type 2 diabetes mellitus receiving treatment with a sulfonylurea.