The impact of HIV-1 co-infection on long-term mortality in patients with hepatitis C: a population-based cohort study

Objective To investigate the impact of HIV co-infection on mortality in patients infected with hepatitis C virus (HCV). Methods From a nationwide Danish database of HCV-infected patients, we identified individuals diagnosed with HCV subsequent to an HIV diagnosis. For each co-infected patient, four control HCV patients without HIV were matched on age, gender and year of HCV diagnosis. Data on comorbidity, drug abuse, alcoholism and date of death were extracted from two healthcare databases. We constructed Kaplan-Meier curves and used Cox regression analyses to estimate mortality rate ratios (MRRs), controlling for comorbidity. Results We identified 483 IICV-IIIV co-infected and 1932 HCV mono-infected patients, yielding 2192 and 9894 person-years of observation with 129 and 271 deaths, respectively. The 5-year probability of survival was 0.74 [95% confidence interval (CI) 0.69-0.80] for HCV-HIV co-infected patients and 0.87 ( 95% CI 0.85-0.89) for HCV mono-infected patients. Co-infection was associated with substantially increased mortality (MRR 2.1, 95% CI 1.7-2.6). However, prior to the first observed decrease in CD4 counts to below 300 cells/mu L, HIV infection did not increase mortality in HCV-infected patients ( MRR 0.9, 95% CI 0.5-1.50). Conclusions HIV infection has a substantial impact on mortality among HCV-infected individuals, mainly because of HIV-induced immunodeficiency.