Potential Impact of Biologic Use on Asthma-Related Hospitalization: An Epidemiological Study in Hong Kong

While the individual effects of biologics in asthma are well demonstrated, the potential impact of the use of biologics on overall asthma-related hospitalization at a population-based level has not been reported.

A territory-wide study conducted in Hong Kong, involving all adult patients with asthma managed in Hospital Authority. The primary outcome was the change in asthma-related hospitalization from 2014 to 2023, correlating with the number of biologic use among patients with asthma and adjusted for Air Quality Health Index and influenza case number.

The weekly asthma-related hospitalization was 96 episodes at the start of the study period and 78 episodes at the end of the study period. There was a significant reduction of asthma-related hospitalization associated with biologic usage, giving the estimated risk ratio of 0.994 (95% CI = 0.991-0.996, p value < 0.05). The estimated break-point for the change in asthma-related hospitalization was at Week 169 (95% CI = 130.3-207.7), which was the week of 19/3/2017 to 25/3/2017. The slopes before and after the break-point were 0.022 and -0.191 with the difference in the two slope estimates being significant (p < 0.001) according to the Davies test. The significant difference in the slope before and after the break-point suggested that beyond Week 169, there was a trend of significant reduction in asthma-related hospitalization.

We observed a reduction in asthma-related hospitalizations throughout the study period with a potential temporal association with the increase in biologic prescription. While biologics provided benefits in individual level, the possible benefits in a population-based level could be related to a more comprehensive care in severe asthma patients from the introduction of biologics for severe asthma.