SAN FRANCISCO, CA—Although low levels of 25-OH vitamin D are associated with an advanced level of fibrosis in hepatitis C virus (HCV) infection, such levels are not predictive for rates of sustained virologic response at 12 weeks (SVR12), a prospective study presented at The Liver Meeting® 2015 concluded.
The study evaluated the association of pretreatment vitamin D level with stage of fibrosis in patients with HCV and assessed change in level when patients were treated with direct acting antiviral therapy.
David W. Backstedt, MD, of Banner University Medical Center in Phoenix, AZ, delineated vitamin D levels prior to treatment initiation and at end of treatment response in 218 consecutively enrolled patients. This included 37 patients treated with pegylated interferon alfa 2a + sofosbuvir + ribavirin; 117 with sofosbuvir + ribavirin, 51 patients with sofosbuvir + simeprevir; 11 patients with ledipasvir + sofosbuvir, and 2 patients with ledipasvir + sofosbuvir + ribavirin.
Significant vitamin D level changes over time were assessed, controlling for the covariates of age, gender, and BMI.
A total of 61.5% of the patients were genotype 1 and 56% were cirrhotic. Among the 36% who were treatment-experienced, 26% were non-responders and 10% were relapsers. End of treatment response (ETR) was observed in 98% of patients (n=213), with 79% (n=172) achieving SVR12, 19% of whom relapsed.
Dr. Backstedt and colleagues found frequency of low pretreatment vitamin D level, defined as <20ng/dL, to be significantly higher in the 123 patients with cirrhosis, 67%, compared with 33% among those without cirrhosis (P=0.009).
Pretreatment vitamin D levels negatively correlated with end-stage liver disease (MELD score [r= -0.231; P<0.05) and total bilirubin (R= -0.239; P<0.05), they reported, “highlighting the importance of global hepatic dysfunction and attendant cholestasis in this phenomenon.”
Although vitamin D level increased during direct acting antiviral therapy, this change was not significant, regardless of fibrosis stage or SVR12 achievement. Multivariate regression analysis found that pretreatment, end of treatment, or change between pretreatment and end of treatment in the 25-OH vitamin D level “was not predictive of SVR12,” they concluded.