The impact of adherence and an intervention program on patient outcomes and costs in chronic hepatitis C infection

Abstract

<bold>Background and aims:</bold> Both observational studies and randomized trials have shown that higher medication adherence is associated with improved outcomes in patients with chronic hepatitis C infection (CHC). Little evidence exists on the association between adherence and health care costs. We sought to evaluate the impact of adherence on long-term outcomes and costs in a population of patients with CHC genotype 1 receiving peginterferon and ribavirin (PEG-RBV). We also evaluated the impact of a potential intervention to improve adherence on long-term costs and patient outcomes. <bold>Methods:</bold> We utilized a cohort Markov model describing the natural history of hepatitis C infection in a population of 50 year-old treatment-experienced adults to evaluate the following health states: CHC, compensated cirrhosis, decompensated cirrhosis, hepatocellular carcinoma, liver transplant, liver transplant survivor, and death. Using previously published data from the HALT-C trial, we modeled four levels of medication receipt: >80% PEG-RBV, >80% PEG/<80% RBV, <80% PEG/<80% RBV, and <80% PEG-RBV. The costs and quality-adjusted life years (QALYs) associated with moving patients to higher level of adherence was compared to the cost associated with a nursing-based intervention program. Time horizons of 5, 10, 20, 30 years and lifetime were evaluated. <bold>Results: </bold> Over a lifetime horizon, we compared patients with the highest adherence versus lowest adherence, and found the following reductions in liver-related events: 9.9% compensated cirrhosis, 4.7% decompensated cirrhosis, 1.4% hepatocellular carcinoma, and 0.5% liver transplant. The potential cost savings over a lifetime as patients move from a cohort of lower SVR to greater SVR ranged from $12,820-$62,690, with a 1% increase in SVR associated with savings of $2137-$3284. <bold>Conclusion: </bold> Interventions that increase patient adherence should improve outcomes in this population and have the potential to reduce costs.