Objective:To characterize the association of ambient particulate matter (PM) pollution of different sizes (particulate matter ≤1 µm in aerodynamic diameter [PM1], PM2.5, and PM10) with in-hospital case fatality among stroke patients in China.Methods:We collected hospitalizations due to stroke in four provinces in China from 2013 to 2019. Seven-day and annual averages of PM prior to hospitalization were estimated using bilinear interpolation and residential addresses. Associations with in-hospital case fatality were estimated using random-effects logistic regression models. Potential reducible fraction and the number of fatalities attributed to PM were estimated using a counterfactual approach.Results:Among 3,109,634 stroke hospitalizations (mean age 67.23 [standard deviation 12.22]; 1,765,644 [56.78%] male), we identified 32,140 in-hospital stroke fatalities (case fatality rate 1.03%). Each 10 µg/m3 increase in 7-day average (short-term) exposure to PM was associated with increased in-hospital case fatality: odds ratios (ORs) were 1.058 (95% confidence interval [CI]: 1.047-1.068) for PM1, 1.037 (95% CI: 1.031-1.043) for PM2.5, and 1.025 (95% CI: 1.021-1.029) for PM10. Similar but larger ORs were observed for annual averages (long-term): 1.240 (95% CI: 1.217-1.265) for PM1, 1.105 (95% CI: 1.094-1.116) for PM2.5, and 1.090 (95% CI: 1.082-1.099) for PM10. In counterfactual analyses, PM10 was associated with the largest potential reducible fraction in in-hospital case fatality (10% [95% CI: 8.3%-11.7%] for short-term exposure and 21.1% [19.1%-23%] for long-term exposure), followed by PM1 and PM2.5.Conclusion:PM pollution is a risk factor for in-hospital stroke-related deaths. Strategies that target reducing PM pollution may improve the health outcomes of stroke patients.

BackgroundFew studies have examined the effects of ambient particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5) on hospital cost and length of hospital stay for respiratory diseases in China.MethodsWe estimated ambient air pollution exposure for respiratory cases through inverse distance-weighted averages of air monitoring stations based on their residential address and averaged at the city level. We used generalised additive models to quantify city-specific associations in 11 cities in Shanxi and a meta-analysis to estimate the overall effects. We further estimated respiratory burden attributable to PM2.5 using the standards of WHO (25 µg/m3) and China (75 µg/m3) as reference.ResultsEach 10 µg/m3 increase in lag03 PM2.5 corresponded to 0.53% (95% CI: 0.33% to 0.73%) increase in respiratory hospitalisation, an increment of 3.75 thousand RMB (95% CI: 1.84 to 5.670) in hospital cost and 4.13 days (95% CI: 2.51 to 5.75) in length of hospital stay. About 9.7 thousand respiratory hospitalisations, 132 million RMB in hospital cost and 145 thousand days of hospital stay could be attributable to PM2.5 exposures using WHO’s guideline as reference. We estimated that 193 RMB (95% CI: 95 to 292) in hospital cost and 0.21 days (95% CI: 0.13 to 0.30) in hospital stay could be potentially avoidable for an average respiratory case.ConclusionSignificant respiratory burden could be attributable to PM2.5 exposures in Shanxi Province, China. The results need to be factored into impact assessment of air pollution policies to provide a more complete indication of the burden addressed by the policies.

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