Association of comorbidities and medications with risk of asthma exacerbation in pediatric patients: a retrospective study using Japanese claims data.

Asthma exacerbation impairs the quality of life of pediatric patients and negatively impacts future respiratory function and health economics. Several risk factors associated with exacerbations have been identified; however, most studies report the risk of each factor. Therefore, this study aimed to evaluate the risk of each factor and a combination of factors. We performed a retrospective cohort study using Japanese claims data and extracted factors associated with exacerbations using multivariate Cox proportional hazards regression and stepwise method. Risk scores were then calculated from the extracted factors and validated by tenfold cross validation. Of the 1,748,111 asthma patients in the database, the data of 14,980 were extracted, and 1988 (13.3%) had exacerbation. Factors associated with asthma exacerbation were age of 3-5 years, exacerbation history before cohort entry date, allergic rhinitis, chronic sinusitis, otitis externa, blepharitis, upper respiratory infections, urticaria, LTRA prescription, were determined. A four-level risk score was calculated from 9-factors and the AUC derived from cross validation was 0.700. Most factors extracted in our study are consistent with those of previous studies. We showed that combining each factor is more helpful in assessing the increased risk of asthma exacerbation than assessing each factor alone.