The viral hepatitis B care cascade: a population-based comparison of immigrant groups

The global burden of viral hepatitis B is substantial and monitoring infections across the care cascade is important for elimination efforts. There is little information on care disparities by immigration status and we aimed to quantify disease burden among immigrant subgroups. In this population-based retrospective cohort study, we used linked laboratory and health administrative records to describe the HBV care cascade in five distinct stages: 1) lifetime prevalence; 2) diagnosis, 3) engagement with care; 4) treatment initiation; and 5) treatment continuation. Infections were identified based on at least one reactive antigen or nucleic acid test, and lifetime prevalence was estimated as the sum of diagnosed and estimated undiagnosed cases. Care cascades were compared between long-term residents and immigrant groups, including subgroups born in hepatitis B endemic countries. Stratified analyses and multivariable Poisson regression were used to identify drivers for cascade progression. Between January 1997 and December 2014, 2,014,470 individuals were included, 50,475 with infections, of whom 30,118 were engaged with care, 11,450 initiated treatment, and 6,554 continued treatment greater than one year. Lifetime prevalence was estimated as 163,309 (1.34%) overall, 115,722 (3.42%) among all immigrants, and 50,876 (9.37%) among those from highly endemic countries. Compared to long-term residents, immigrants were more likely to be diagnosed (aRR: 4.55 [95%CI: 4.46, 4.63]), engaged with care (aRR: 1.07 [95%CI: 1.04, 1.09]), and initiate treatment (aRR: 1.09 [95%CI: 1.03, 1.16]). In conclusion, immigrants fared well compared to long-term residents along the care cascade, having higher rates of diagnosis and slightly better measures in subsequent cascade stages, although intensified screening efforts and better strategies to facilitate linkage to care are still needed.