Effects of short-term air pollution exposure on respiratory infection-related healthcare burden in kidney transplant recipients.

OBJECTIVES: Kidney transplant recipients are highly susceptible to respiratory tract infections (RTIs), and short-term exposure to ambient air pollution may aggravate their clinical outcomes. However, evidence regarding the effects of specific pollutants on hospitalization burden in this population remains limited. This study aims to investigate the effects of pollutants such as PM2.5 on hospitalization burden after RTIs in kidney transplant recipients. METHODS: This retrospective time-series study included 874 kidney transplant recipients who were hospitalized for RTIs at the Third Xiangya Hospital of Central South University between 2017 and 2023. High-resolution environmental data were used to assess daily exposure to 6 ambient air pollutants, namely PM2.5, PM10, SO2, NO2, CO, and O3, within the 7 days before the onset of RTI symptoms. Distributed lag non-linear models (DLNMs) were applied to evaluate pollutant-specific lagged and cumulative associations between the 6 ambient air pollutants and hospitalization costs and length of hospital stay, with adjustment for meteorological conditions and individual-level variables. RESULTS: PM2.5 showed the most significant association with hospitalization burden. At a cumulative exposure level of 160 µg/m3, hospitalization costs increased by 9 544.5 yuan (95% CI 2 548.8 to 21 637.7). When PM2.5 exposure reached 200 µg/m3 on lag day 0, it was associated with prolonged hospital stay and increased hospitalization costs. PM10 showed a trend toward dose-dependent cumulative effect on length of hospital stay, with a relative risk of 1.63 at 300 µg/m3 (95% CI 0.18 to 15.94). SO₂ levels above 75 µg/m3 were also associated with increased hospitalization burden. In contrast, no consistent or significant associations were observed for CO, NO2, or O3. CONCLUSIONS: Short-term exposure to higher levels of PM2.5, PM10, and SO2 significantly increases the clinical and economic burden of RTIs in kidney transplant recipients. These findings highlight the importance of developing targeted air pollution prevention and control strategies to protect susceptible patient populations.