Vitamin D status does not predict sustained virologic response or fibrosis stage in chronic hepatitis C genotype 1 infection

Abstract

Background & aims: The relationship between vitamin D status and response to antiviral therapy and liver histology in hepatitis C virus genotype 1 (HCV-1) infection remains unclear, with studies to date yielding inconsistent results and failing to use reference assay methodology. We therefore analyzed pre-treatment 25-hydroxyvitamin D [25(OH)D] level, using reference liquid chromatography-tandem mass spectrometry methodology, in a cohort of treatment-naïve patients with HCV-1 to evaluate the association between vitamin D status, virologic response, and liver histology.

Methods: 274 patients, with pre-treatment liver biopsy and up to 48 weeks of pegylated interferon alfa-2a plus ribavirin therapy, were tested for serum 25(OH)D level. Predictors of sustained virologic response (SVR), and variables associated with fibrosis stage, activity grade and 25(OH)D status were identified using multivariate analysis.

Results: Mean 25(OH)D level was 79.6 nmol/L, with a prevalence of 25(OH)D <75 nmol/L and <50 nmol/L of 48% and 16%, respectively. Season, race and geographic latitude were independent predictors of 25(OH)D status, while vitamin D deficiency was more prevalent in those with high activity grade (21% vs. 11%; p=0.03). Mean 25(OH)D level was lower (76.6 vs. 84.7 nmol/L; p=0.03) and 25(OH)D <75 nmol/L more prevalent (53% vs. 40%; p=0.03) in patients with an SVR, but no association between 25(OH)D status and SVR was found in multivariate analysis. Mean 25(OH)D level did not vary between fibrosis stage or activity grade.

Conclusions: Baseline 25(OH)D level is not independently associated with SVR or fibrosis stage in HCV-1, but vitamin D deficiency is associated with high activity grade.