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Short-term exposure to ambient air pollution and readmissions for heart failure among 3660 post-discharge patients with hypertension in older Chinese adults
  1. Ruijun Xu1,
  2. Qi Tian2,
  3. Jing Wei3,
  4. Yunshao Ye2,
  5. Yingxin Li1,
  6. Qiaoxuan Lin2,
  7. Yaqi Wang1,
  8. Likun Liu1,
  9. Chunxiang Shi4,
  10. Wenhao Xia5,
  11. Yuewei Liu1
  1. 1 Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
  2. 2 Department of Statistics, Guangzhou Health Technology Identification and Human Resources Assessment Center, Guangzhou, Guangdong, China
  3. 3 Department of Atmospheric and Oceanic Science, Earth System Science Interdisciplinary Center, University of Maryland at College Park, College Park, Maryland, USA
  4. 4 Meteorological Data Laboratory, National Meteorological Information Center, Beijing, China
  5. 5 Department of Hypertension and Vascular Disease, Sun Yat-sen University First Affiliated Hospital, Guangzhou, Guangdong, China
  1. Correspondence to Dr Yuewei Liu, Sun Yat-sen University, Guangzhou, Guangdong 510080, China; liuyuewei{at}


Background Despite ambient air pollution being associated with various adverse cardiovascular outcomes, the acute effects of ambient air pollution on hospital readmissions for heart failure (HF) among post-discharge patients with hypertension remain less understood.

Methods We conducted a time-stratified case-crossover study among 3660 subjects 60 years or older who were admitted to hospital for HF after discharge for hypertension in Guangzhou, China during 2016–2019. For each subject, individualised residential exposures to ambient particulate matter with an aerodynamic diameter ≤1 µm (PM1), ≤2.5 µm (PM2.5), ≤10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone were extracted from our validated grid dataset.

Results An IQR increase of lag 04-day exposure to PM1 (IQR: 11.6 μg/m3), PM2.5 (IQR 21.9 μg/m3), PM10 (IQR 35.0 μg/m3), SO2 (IQR 4.4 μg/m3), NO2 (IQR 23.3 μg/m3) and CO (IQR 0.25 mg/m3) was significantly associated with a 9.77% (95% CI 2.21% to 17.89%), 8.74% (95% CI 1.05% to 17.00%), 13.93% (95% CI 5.36% to 23.20%), 10.81% (95% CI 1.82% to 20.60%), 14.97% (95% CI 8.05% to 22.34%) and 7.37% (95% CI 0.98% to 14.16%) increase in odds of HF readmissions, respectively. With adjustment for other pollutants, the association for NO2 exposure remained stable, while the associations for PM1, PM2.5, PM10, SO2 and CO exposures became insignificant. Overall, an estimated 19.86% of HF readmissions were attributable to NO2 exposure, while reducing NO2 exposure to the WHO and China air quality standards would avoid 12.87% and 0.54% of readmissions, respectively. No susceptible populations were observed by sex, age or season.

Conclusion Short-term exposure to ambient NO2 was significantly associated with an increased odds of HF readmissions among post-discharge patients with hypertension in older Chinese adults.


Data availability statement

Data are available in a public, open access repository. The air pollution data are available at: The clinical and meteorological data are not publicly available.

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Data availability statement

Data are available in a public, open access repository. The air pollution data are available at: The clinical and meteorological data are not publicly available.

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  • RX and QT contributed equally.

  • Contributors RX searched the literature, conducted the data analysis, interpreted the data and drafted the manuscript. QT acquired the data and drafted the manuscript. JW acquired the data and conducted the data analysis. CS acquired the data. YL designed the study, acquired the data, directed the study’s implementation, designed the analytical strategy and obtained the funding. All authors critically revised the manuscript. YL and WX share joint correspondence in this work and are responsible for the overall content as guarantors.

  • Funding This work was supported by the Health Commission of Guangdong Province (grant number B2019196), the Health Commission of Hubei Province (grant number WJ2019Z016) and the National Natural Science Foundation of China (grant number 81671379).

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  • Competing interests None declared.

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