Effects of KCNQ1 Polymorphisms on the Therapeutic Efficacy of Oral Antidiabetic Drugs in Chinese Patients With Type 2 Diabetes

The aim of this study was to explore the impact of KCNQ1 variants on the responses to oral antidiabetic drugs in a Chinese study population. A 48‐week randomized pharmacogenetics study compared the effects of repaglinide and rosiglitazone in 209 newly diagnosed patients with type 2 diabetes. In the repaglinide cohort, individuals who were rs2237892 TT homozygotes exhibited lower 2‐h glucose levels and significantly higher cumulative attainment rates of target 2‐h glucose levels ( P log‐rank = 0.0383) than the C allele carriers; patients with a greater number of rs2237892 C alleles showed larger augmentations in both fasting insulin and homeostasis model assessment of insulin resistance (HOMA‐IR) ( P = 0.0166 and 0.0026, respectively); moreover, the rs2237895 C allele was also associated with greater increments in both fasting insulin and HOMA‐IR ( P = 0.0274 and 0.0259, respectively). In contrast, only an association between rs2237897 and decrease in 2‐h glucose levels was detected in the rosiglitazone cohort ( P = 0.0321). Our results indicated that KCNQ1 polymorphisms are associated with repaglinide efficacy, and might also be associated with rosiglitazone response, in Chinese patients with type 2 diabetes. Clinical Pharmacology & Therapeutics (2011) 89 3, 437–442. doi: 10.1038/clpt.2010.351