All-cause acute care hospitalization rates of immigrants and the Canadian-born population: A linkage study.

Background: As Canadian immigration levels increase, knowledge concerning immigrant health becomes increasingly important for health system policy and planning. This study compares the rate of all-cause hospitalization among immigrants with that of their Canadian-born counterparts.

Data and methods: Using records from the Discharge Abstract Database (2004/2005 to 2016/2017) and the Ontario Mental Health Reporting System (2006/2007 to 2017/2018) linked to the 2016 Longitudinal Immigration Database, this study compared the age-standardized hospitalization rates (ASHRs) among immigrants with those of the Canadian-born population; the latter were obtained from a linkage based on the 2011 National Household Survey. Comparisons were made at the International Classification of Diseases chapter level by immigrant landing year, admission category and world region of birth. Quebec data were not available.

Results: Overall, ASHRs among immigrants were lower than for the Canadian-born population. Immigrants in the economic class had the lowest ASHR, followed by those in the family class and among refugees. After pregnancy was excluded, leading hospitalization causes were similar for immigrants and the Canadian-born population, where top causes included digestive system and circulatory diseases, injuries, and cancer. In male and female immigrants, the ASHRs were lowest among those from East Asia. By landing year, males arriving earlier had the highest ASHR compared with the most recent arrivals. When pregnancy was excluded and while the differential in ASHRs among females by landing year remained, the magnitude was smaller.

Interpretation: These results corroborate those from previous studies suggesting a healthy immigrant effect, but also reveal heterogeneity in ASHRs within the immigrant population. They provide a baseline for comparison of health status between populations, which enables further monitoring and informs health-system policy and planning.