Heat-Related Risks of Kidney Disease Among People With Disabilities: A Nationwide Case-Crossover Study in South Korea

Background: Kidney diseases impose a substantial and growing healthcare burden worldwide, and emerging evidence suggests that heat exposure may exacerbate acute renal conditions. People with disabilities are known to be particularly vulnerable to heat-related health risks; however, few studies have examined heterogeneity in heat-related kidney outcomes by specific disability type.

Methods: We conducted a nationwide time-stratified case-crossover study using the Korean National Health Insurance Database from 2015 to 2023. Emergency department (ED) visits for kidney and urinary tract diseases (ICD-10 N00–N39) during summer months (June–September) were analyzed among 3,866,115 individuals with disabilities and 1:1 matched non-disabled controls. Disabilities were classified into five categories: physical, brain lesion, sensory, developmental, and mental disabilities. Daily mean temperature was obtained from ERA5-Land reanalysis data and expressed as local percentiles to account for climatic acclimatization. Distributed lag non-linear models combined with conditional logistic regression were applied, adjusting for PM₂.₅ and ozone concentrations. Heat-related risks were estimated by comparing the 99th percentile temperature to the 75th percentile.

Results: Overall, heat exposure was associated with increased ED visits for kidney diseases, with substantial heterogeneity by disability type. Individuals with mental disabilities exhibited the most pronounced vulnerability, particularly for kidney disease and urinary tract infections, showing significantly elevated odds compared with non-disabled counterparts. Physical and brain lesion disability groups demonstrated increased risks for acute kidney injury, although similar trends were observed among non-disabled individuals. Sex-stratified analyses revealed stronger heat-related kidney risks among men, especially those with mental disabilities.

Conclusions: Heat-related kidney disease risks differ markedly by disability type and sex, underscoring the importance of disaggregated analyses. These findings highlight the need for disability-specific heat adaptation strategies and targeted public health interventions to mitigate climate-related renal health inequities among people with disabilities.