The effects of air pollution on length of hospital stay for adult patients with asthma.

Length of hospital stay (LOS) of asthma can be a reflection of the disease burden faced by patients, and it is also sensitive to air pollution. This study aims at estimating and validating the effects of air pollution and readmission on the LOS for those who have asthma, considering their readmission history, minimum temperature, and threshold effects of air pollutants. In addition, sex, age, and season were also constructed for stratification to achieve more precise and specific results. The results show that no significant effects of PM2.5 and NO2 on LOS were observed in any of the patients, but there were significant effects of PM2.5 and NO2 on LOS when a stratifying subgroup analysis was performed. The effect of PM10 on LOS was found to be lower than that of PM2.5 and higher than that of NO2 . SO2 did not have a significant effect on LOS for patients with asthma in our study. Our study confirmed that the adverse effects of air pollutants (such as PM10 ) on LOS for patients with asthma existed; in addition, these effects vary for different stratifications. We measured the effects of air pollutants on the LOS for patients with asthma, and this study offers policy makers quantitative evidence that can support relevant policies for health care resource management and ambient air pollutants control.