BackgroundStudies have shown the efficacy of asthma biologics in real-world settings, confirming the generalizability of randomized controlled trial (RCT) results, but studies on more than one biologic are scarce. Accordingly, little is known about the different background characteristics in users of asthma biologics. This study aimed to describe the backgrounds of asthma patients using biologics (omalizumab, mepolizumab, benralizumab, and dupilumab) and examine the effectiveness of these biologics for reducing asthma exacerbations and total systemic corticosteroid doses. MethodsWe conducted a retrospective cohort study using self-controlled methods to evaluate the association between the use of biologics and reduction in exacerbations and hospitalizations using a large-scale health insurance claims database in Japan. ResultsOf 355 continuously treated asthma patients using biologics, 119, 82, 69, and 85 patients were assigned to the omalizumab, mepolizumab, benralizumab, and dupilumab groups, respectively. The baseline characteristics differed among users of biologics. The incidence ratios of exacerbations and hospitalizations during biologics use were 0.68 (95% confidence interval, 0.62–0.74) and 0.65 (0.55–0.77) compared with the period before biologics use. The total systemic corticosteroid dose equivalent to prednisolone per person-year was reduced from a median of 600 [interquartile range, 90–1713] mg to 164 [0–1010] mg (P < .001). Similar results were obtained for individual biologics with a few exceptions. ConclusionsThe background characteristics of biologics users differed in a real-world setting. Our results confirmed findings from RCTs demonstrating that each biologic (omalizumab, mepolizumab, benralizumab, and dupilumab) is associated with decreased exacerbation numbers and corticosteroid-sparing effects, even outside of the controlled settings of RCTs.