Purpose: To estimate the disease burden and lifetime direct medical costs caused by hepatitis C virus (HCV) infection among immigrants in Canada through a Markov cohort model.
Method: A Markov model with one-year cycle length and lifetime horizon was constructed according to HCV epidemiology, pattern of care, and the natural history of HCV among immigrants in Canada. Various resources were used to estimate the input parameters: 2006 Canada Census for the distribution of immigrants by age; WHO report for HCV prevalence by country; literature review for HCV genotype distribution by country; frequency of anti-HCV tests in 2006 in Ontario for HCV detection; medical records of immigrant patients (n=927) for fibrosis distribution, pattern of care, and the prognosis after cirrhosis; publications reporting sensitivity and specificity for HCV antibody test, HCV-induced fibrosis progress, and efficacy of anti-viral therapy; a cost study of 30000 HCV patients in British Columbia, Canada for direct medical costs. Microsimulation with sampling all the distributions of the parameters in the model was conducted with the number of trials representing the immigrant population (n = 5411710) in Canada in 2006 to estimate the loss of life years, lifetime risk of HCV-related complications, and increased lifetime direct medical costs in 2006 Canadian dollars associated with HCV infection among immigrants.
Result: The Markov model included eight branches by age group. Each branch contained 50 health states with 197 variables. The microsimulation of the Markov model estimated immigrants with chronic HCV infection had a shorter life expectancy (33.07 years vs. 38.27 years), higher lifetime risks for hepatocellular carcinoma (42.1%), hepatic decompensation (33.5%), and liver transplant (47.0%), and higher lifetime direct medical costs (584628 dollars vs. 182422 dollars) when compared to immigrants free of HCV infection. Based on estimated HCV prevalence (2.2%) and genotype distribution (70.4% for genotype 1, 4, 5, or and/or 6) among immigrants, the microsimulation of the Markov model taking 2006 immigrant population as a cohort estimated 649405.2 life years lost, an increase of 46778.8 million Canadian dollars in 2006, 39257 decompensated patients, 49734 hepatocellular carcinoma patients, and 55383 liver transplants due to HCV infection.
Conclusion: Our Markov model projected a significant loss of life expectancy and increase of lifetime direct medical costs due to chronic HCV infection among immigrants in Canada.
Candidate for the Lee B. Lusted Student Prize Competition