Background: Asthma hospitalizations declined rapidly in many parts of the world, including Canada, in the 1990s and early 2000s.

Objective: To examine whether the declining trend of asthma hospitalizations persisted in recent years in Canada.

Methods: Using the Canadian comprehensive nationwide hospitalization data (2002-2017), we identified hospital admissions with the main International Classification of Diseases codes for asthma. We analyzed sex-specific age-standardized trends in annual hospitalization rates among pediatric (< 19 years) and adult (19+ years) patients. We used change-point analysis to evaluate any substantial changes in the trends in the sex-age groups.

Results: There were 254,672 asthma-related hospital admissions (59% pediatric, 50% female) during the study period. Among children, age-adjusted annual rates per 100,000 decreased by 55% in females (152-69) and by 60% in males (270-108) from 2002 to 2017. Among adults, the rates decreased by 59% in both sexes (females: 61-25; males: 27-11). Change-point analysis indicated a substantial plateauing of the annual rate in both pediatric (from -15.3 (females) and -25.8 (males) before 2010 to -0.6 (females) and -0.8 (males) after 2010) and adult (from -5.4 (females) and -2.6 (males) before 2008 to -0.6 (females) and -0.2 (males) after 2008) groups.

Conclusion: After a substantial decline in hospital admissions for acute asthma, there has been minimal further decline since 2010 for children and 2008 for adults. In addition to adhering to the contemporary standards of asthma care, novel, disruptive strategies are likely needed to further reduce the burden of asthma.