Category: Federal Forum Posters
Purpose: Direct acting antivirals for hepatitis C are highly effective but are costly. Prior studies have evaluated patient specific factors that may be associated with treatment success rates, including renal function, presence of cirrhosis, race, and concomitant medications. Vitamin D has been associated with treatment outcomes for other infectious diseases. This study aimed to evaluate the potential association of patient vitamin D status to rates of sustained viral response (SVR) for hepatitis C virus (HCV) treatment with sofosbuvir based therapy.
Methods: A retrospective, case-control analysis was completed at a single VA health care system. Patients with a diagnosis of cirrhosis treated with sofosbuvir and ribavirin with or without peginterferon, sofosbuvir and simeprevir with or without ribavirin, or sofosbuvir and ledipasvir with or without ribavirin for HCV between the dates of 1/1/2014 and 12/31/2016 were included in the analysis. Patients must have had a viral load evaluated 11 weeks or later after completion of therapy, documented vitamin d level within one year prior to treatment start or documentation of active supplementation during treatment, and available data to determine baseline creatinine clearance. The primary outcome was SVR defined as documented undetectable viral load 11 weeks or later after therapy completion. Patients with SVR failure constituted the case group and those with SVR success constituted the control group. Vitamin D sufficiency was defined as having a serum level ≥ 30 ng/ml or documented active supplementation during HCV therapy and vitamin D deficiency as a serum level < 30 ng/mL and no documentation of supplementation. Duration of therapy was grouped by those having a planned 24 weeks of therapy compared to those with fewer prescribed weeks. Univariate analysis of vitamin D status, baseline creatinine clearance > 80 ml/min, and duration of therapy was completed. Variables with a p-value < 0.2 in univariate analysis were included in the regression model.
Results: A total of 113 patients were identified for inclusion. The overall treatment success rate was 89.4% (101/113). Successful SVR was reached in 92% of those with vitamin D sufficiency (92/100) versus 69.2% (9/13) of those with vitamin D deficiency (Fisher’s Exact, p<0.05). Success rates in those with CrCl < 80ml/min was 88.5% (46/52) compared to 90.2% (55/61) in those with CrCl > or = to 80 ml/min (p=0.77). Those receiving less than 24 weeks of therapy had SVR rate of 92.5% (86/93) versus 75% (15/20) for those receiving 24 weeks of therapy (Fisher’s Exact, p< 0.037). Duration of therapy and vitamin D status were included in the regression model. Vitamin D status and duration of therapy were independently associated with SVR success with OR for vitamin D status of 6.151 (95% CI, 1.41 – 26.81) and for duration of therapy of 4.85 (95% CI, 1.25 – 18.78).
Conclusion: In patients with a diagnosis of liver cirrhosis treated with sofosbuvir based therapy for HCV, vitamin D sufficiency defined as serum level ≥ 30 ng/ml or active vitamin D supplementation was independently associated with treatment success. A shorter duration of therapy was also found to be independently associated with treatment success, however likely reflects selection bias based on guideline treatment recommendations for extended treatment durations for patients with potentially more challenging to treat characteristics. Further study of the role of vitamin D status in HCV treatment SVR success rates is warranted.