Association between extreme temperature and kidney disease in South Korea, 2003-2013: Stratified by sex and age groups.

Weather conditions due to climate change affect the health directly and indirectly. Previous studies have shown associations with temperature, heat wave, and cold spell, and these do not only result in mortality from cardiovascular disease, respiratory disease, etc., but also in morbidity. This study aimed to quantify the relative risk for hospital admissions related to ambient temperature for genitourinary system diseases, which are representative of metabolic disease. We conducted a nationwide retrospective cohort study using claims data generated by medical services for diseases of the urinary system. The data was based on medical claims data from 16 districts in South Korea, to the nationwide level between 2003 and 2013. A total of 1,255,671 hospital admissions through the emergency department because of diseases of the genitourinary system were reported within the study period. The overall cumulative relative risk at the 99th percentile vs. the minimum morbidity percentile for renal diseases was 1.252 (95% confidence interval 1.211 to 1.294) in Seoul, 1.252 (1.21 to 1.296) in Busan, 1.236 (1.196 to 1.276) in Daegu, 1.237(1.197 to 1.279) in Gwangju, and 1.258 (1.218 to 1.299) in Gyeonggi-do, 1.278 (1.211 to 1.349) in Chungcheongbuk-do, 1.291 (1.235 to 1.35) in Gyeongsangnam-do. In the group of men over 65 years, the overall cumulative RR was high and statistically significant in acute kidney injury (AKI). But we could not find the effect of high temperature for chronic kidney disease (CKD). The association were rather opposite, but not statistically significant. Our nationwide study not only demonstrates relative risk considering lag effects associated with ambient temperature and trends in hospital admissions through the emergency department for genitourinary disorders but also observed differences among disease groups.