Climate-associated burden of chronic kidney disease due to non-optimal temperature in G20 countries: evidence from a multicountry longitudinal study.

BACKGROUND: Chronic kidney disease (CKD) is a growing global health burden, and non-optimal temperature is increasingly recognized as an environmental contributor; however, the long-term population-level mortality burden attributable to temperature exposure across the Group of Twenty (G20) has not been systematically characterized. METHODS: A multicountry longitudinal analysis was conducted for the G20 overall and 19 member countries from 2010 to 2023. Deaths from CKD attributable to non-optimal temperature, attributable percent, and temporal trends were estimated and stratified by sex and age group, with high temperature and low temperature assessed separately. Long-term trends were quantified using the estimated annual percentage change (EAPC). RESULTS: Across the G20, total CKD deaths increased from 599,066 in 2010 to 838,263 in 2023, and the CKD death rate rose from 14.00 to 17.67 per 100,000 (EAPC 1.74). CKD deaths attributable to non-optimal temperature increased from 45,071 to 58,041 (+ 28.84%), while the attributable percent declined from 7.52% to 6.92% (EAPC - 0.36). In 2023, attributable fractions ranged from 0.93% in Indonesia to 15.33% in Saudi Arabia, and attributable deaths were highest in the United States (11,950) and China (11,932). Low temperature dominated the burden (39,435 to 50,617 deaths; 6.04% in 2023), whereas high temperature contributed a smaller share (0.94% in 2023; 7,846 deaths) with greater instability. The burden was greatest in adults aged ≥ 75 years, while younger age groups showed declining attributable deaths. National EAPC patterns were heterogeneous, with declines in several countries (e.g., Mexico, United Kingdom, France, Germany, Japan) but increases or near-stable trends in others, notably Indonesia and the Russian Federation. CONCLUSIONS: Non-optimal temperature contributes meaningfully to CKD mortality in the G20, which is examined here as a policy-relevant group rather than a global proxy. The marked heterogeneity highlights the need for tailored adaptation, especially for cold exposure and aging populations.