Influence of Two Common Polymorphisms in theEPHX1Gene on Warfarin Maintenance Dosage: A Meta-Analysis

We conducted a meta-analysis to investigate the influence of two common single nucleotide polymorphisms (SNPs) (rs2292566 G>A and rs4653436 A>G) in theEPHX1gene on warfarin maintenance dosages. Relevant literatures were searched using thePubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CBM, andCNKIdatabases without any language restrictions. STATA Version 12.0 software (Stata Corporation, College Station, TX, USA) was used for this meta-analysis. Standard mean difference and its corresponding 95% confidence interval (95% CI) were calculated. Seven studies met the inclusion criteria, including 2,063 warfarin-treated patients. Meta-analysis results illustrated thatEPHX1rs2292566 G>A polymorphism might be strongly correlated with a higher maintenance dose of warfarin. However, no interaction ofEPHX1rs4653436 A>G polymorphism with warfarin maintenance dosage was detected. A further subgroup analysis based on stratification by ethnicity indicated thatEPHX1rs2292566 G>A polymorphism was positively correlated with warfarin maintenance dosage among Caucasians, but not Asians. No associations were observed betweenEPHX1rs4653436 A>G polymorphism warfarin maintenance dosage among both Caucasians and Asians. Our meta-analysis provides robust and unambiguous evidence thatEPHX1rs2292566 polymorphism may affect the maintenance dose of warfarin in Caucasians.