Incidence and cost of treatment-emergent comorbid events in insured patients with chronic hepatitis C virus infection: a retrospective cohort study

BACKGROUND: Treatment-emergent comorbid events (TECs) are common In patients initiating treatment with pegylated interferon alpha (PEG-IFN-alfa) and ribavirin for chronic hepatitis C virus (HCV) infection. The purpose of this study was to estimate the incidence and incremental cost of these events. METHODS: In a retrospective cohort analysis of healthcare claims, we studied patients with HCV who were newly treated with PEG-IFN-alfa/ribavirin between 2006 and 2008. TECs were defined by new medical/pharmacy claims for predefined conditions in the 12 months after treatment initiation. The net incremental cost of the TECs was the difference between baseline and follow-up costs for these comorbidities and their treatment, excluding PEG-IFN-alfa/ribavirin costs. RESULTS: Of 3,795 newly treated patients, 1,269 (mean age 50.2, 36.2% female) met the selection criteria. New TECs were common, with 61.6% of patients having ≥1 event. Anemia was identified in 29.2% of patients, fatigue in 16.4%, depression in 11.5%, and neutropenia in 11.0%. The mean incremental cost for the predefined TEC in the postindex period was $6,377 ($2,782 for medical and $3,595 for pharmacy claims). CONCLUSIONS: In an insured US cohort with chronic HCV infection, TECs with PEG-IFN-alfa/ribavirin were common and increased costs by approximately $6,000 per treated patient. This estimate may be conservative because it excludes indirect costs. Costs might increase with new regimens that include a protease inhibitor because additional TECs may be expected. Better-tolerated therapies that reduce the financial burden on the healthcare system and improve patient experience are needed.