The current and future temperature-related mortality burden of cause-specific kidney diseases: A national case-crossover study in China.

BACKGROUND

Many studies have investigated the association of temperature with non-accidental mortality, but there is limited evidence on the temperature-related mortality burden of kidney diseases. This study aims to assess the mortality impact of temperatures on cause-specific kidney in China.

METHODS

We conducted a time-stratified case-crossover study using mortality data from kidney diseases across 2790 counties/districts in China from 2003 to 2022. We used conditional logistic regression in conjunction with distribution lag nonlinear model (DLNM) to examine the association between temperature and kidney disease mortality. Furthermore, we projected the mortality burden of kidney diseases attributed to temperature under diverse climate change scenarios in China in the future.

RESULTS

The study included 914,177 kidney disease fatalities, revealing an inversely J-shaped association between temperature and kidney disease mortality across various subgroups. Both extreme cold (Odds ratios [OR] = 1.34, 95 % CI: 1.27-1.41) and extreme heat (1.06, 95 % CI: 1.02-1.10) were linked to increased kidney mortality, with a more pronounced effect in females [1.08(95 % CI: 1.02-1.14) for extreme heat, 1.34(95 % CI: 1.24-1.46) for extreme cold], the elderly [1.07(95 % CI: 1.03-1.12) for extreme heat, 1.35(95 % CI: 1.26-1.45) for extreme cold ] and those with acute kidney disease [1.10(95 % CI: 0.96-1.26)] for extreme heat, 1.43(95 % CI: 1.19-1.73) for extreme cold]. Nationwide, temperatures accounted for 9.28 % (95 % CI: 9.17 %-9.40 %) of kidney disease mortality, with 9.15 % (95 % CI: 9.03 %-9.26 %) for cold and 0.13 % (95 % CI: 0.12 %-0.14 %) for heat, and temperature-related AF of acute kidney disease was the greatest (attributable fraction [AF] = 11.00 %,95 %CI:10.71 %-11.31 %). Projections suggest that temperature-related AFs would rise from 11.39 % (95 % CI: 8.19 %-13.89 %) in the 2050s to 15.26 % (95 % CI: 10.30 %-18.68 %) in the 2090s under SSP5-8.5, with heat-related AFs increasing from 2.82 % (95 % CI: 1.8 %-4.20 %) to 7.12 % (95 % CI: 4.23 %-10.09 %) and cold-related AFs decreasing from 8.57 % (95 % CI: 5.71 %-9.89 %) to 8.14 % (95 % CI: 5.22 %-8.81 %).

CONCLUSION

Our study indicates that temperatures are significantly associated with the mortality risk and burden of kidney diseases in China, and temperature-related mortality is expected to increase in the future, particularly from heat. Our findings indicate that kidney diseases are vulnerable to ambient temperature in the context of climate change.