Short‐ and Long‐Term Healthcare Costs Attributable to Hepatitis B Among Newcomers to Ontario, Canada: A Matched Cohort Study

BACKGROUND: Healthcare expenditures across the clinical trajectory of hepatitis B virus (HBV) infection are inadequately characterized, particularly among immigrants. Our aim is to quantify HBV-attributable short- and long-term costs among a population of newcomers to the province of Ontario. METHODS: We performed a cost-of-illness study with an incidence-based, matched cohort design, employing linked population-based laboratory and health administrative data, and permanent residence data from Immigration, Refugees and Citizenship Canada (IRCC). We identified newcomers diagnosed with HBV between January 1, 2004, and December 31, 2018, and dichotomized the study cohort into individuals with or without liver complications before diagnosis. We used propensity score matching and phase-of-care costing to quantify monthly attributable costs for each of six HBV phases and longitudinal costs for one, five, and ten years following diagnosis. Costs were quantified in 2021 Canadian dollars. RESULTS: Among n = 30,677 newcomers with HBV, 2.7 percent had complications before diagnosis. Mean monthly phase costs were higher for individuals with complications before diagnosis relative to those without for prediagnosis care ($439, 95% CI: $250-$645 vs. $22, 95% CI: $12-$34), initial care for HBV ($1545, 95% CI: $1196-$1945 vs. $331, 95% CI: $299-$369), continuing care for HBV ($537, 95% CI: $314-$760 vs. $73, 95% CI: $55-$92), and final care ($7271, 95% CI: $3749-$10,747 vs. $3430, 95% CI: $1813-$5061). CONCLUSIONS: Findings emphasize the dynamic nature of HBV-attributable costs and highlight the importance of care following diagnosis and complication onset.