Association of vitamin D receptor gene polymorphisms with response to peginterferon plus ribavirin in Asian patients with chronic hepatitis C

Background/Purpose: Recent studies have shown that serum vitamin D deficiency is a negative predictor of response to peginterferon plus ribavirin therapy for Caucasian patients with chronic hepatitis C (CHC). Whether vitamin D receptor (VDR) gene polymorphisms associate with antiviral response in Asian CHC patients remains unclear. Methods: We recruited 139 Asian patients with CHC genotype-1 who achieved 80/80/80 adherence of response-guided peginterferon plus ribavirin therapy. BsmI rs1544410, ApaI rs7975232, and TaqI rs731236 were genotyped and related to clinical and virological features and to treatment outcome. Results: Patients carrying bAt [CCA] haplotype (p=0.033), ApaI CC genotype (p = 0.033), and TaqI AA genotype (p = 0.037) had a higher HCV load as compared to those with other haplotypes, ApaI CA/AA genotype and TaqI AG genotype, respectively. A sustained virological response (SVR) was achieved in 74 (53%) of the patients. Polymorphisms in VDR gene did not correlate with rapid virological response and SVR achievement. Stepwise logistic regression analysis showed that rs12979860 CC type [odds ratio (OR): 5.56, p=0.007], platelet counts ≥ 15 × 10¹⁰/L (OR: 4.80, p=0.001), and rapid virological response achievement (OR: 8.36, p<0.001) were independent factors of SVR. Conclusion: Despite their associations with high hepatitis C virus load, VDR gene polymorphisms are not related to the response to peginterferon plus ribavirin therapy in Asian CHC patients.