Heat Wave and Mortality Burden of Chronic Kidney Disease: Current Assessment and Future Projection in China.

OBJECTIVE

Although many studies have examined temperature-related non-accidental mortality, the impact of heat waves on the mortality burden of chronic kidney disease (CKD) remains poorly understood. This study aimed to assess the CKD mortality burden associated with heat waves in China under global warming.

METHODS

Mortality data on CKD from 2,790 counties/districts in China from 2004 to 2022 were collected from the Chinese Center for Disease Control and Prevention; meteorological data for the same period were obtained from the fifth-generation European Reanalysis Land dataset. A time-stratified case-crossover design combined with a distributed lag nonlinear model was used to examine the association between heat waves and CKD mortality. Future CKD mortality burdens attributable to heat waves under climate change and future population scenarios were projected.

RESULTS

In total, 236,260 CKD deaths were included in this study. Compared to that during non-heat wave days, CKD mortality increased by 3.48% (95% confidence interval [ CI]: 1.67% to 5.33%) during heat waves, and the mortality risk escalated by 2.48% (95% confidence interval [ CI]: 0.12% to 4.91%) for each 1 °C increment during heat wave days. Stratified analyses revealed that CKD mortality risks were greater for women (Excess Risk [ER] = 5.52%, 95% CI: 2.71% to 8.40%), individuals aged 65 years and older (ER = 4.60%, 95% CI: 2.30% to 6.96%), and people in mesic/cold regions (ER = 6.20%, 95% CI: 1.13% to 11.53%). The projections showed that the attributable fraction(AF) of CKD mortality due to heat waves would rise from 0.64% (95% CI: 0.52% to 0.78%) in the 2020s to 2.44% (95% CI: 1.97% to 2.95%) in the 2090s under the SSP5-8.5 scenario, with the highest burden in southeastern China, including Hainan (3.31%, 95% CI: 1.66% to 5.02%), Yunnan (3.05%, 95% CI: 1.46% to 4.75%), and Guangdong Province (2.84%, 95% CI: 1.24% to 4.41%).

CONCLUSION

This nationwide study demonstrated that exposure to heat waves significantly increased the mortality risk of CKD, and that women, older individuals, and people in mesic/cold regions are more susceptible to heat waves. Global warming will significantly increase the future CKD mortality burden attributed to heat waves, particularly in southeastern China. Our findings emphasize the need to address CKD in the context of ongoing climate change.