Do weather parameters affect the incidence of renal colic in a predominantly warm country? A multicenter study

Purpose: To determine whether there is any effect of weather parameters on the incidence of renal colic patients presenting to emergency rooms (ERs) during the hottest season in Israel. Materials and Methods: This retrospective multicenter study involved all ER admissions related to renal colic in nine centres throughout Israel between 2010 and 2017. The collected data included the date of ER visits, the patients’ age and sex, and the weather features of ambient temperature, wind velocity, noon heat index, and barometric pressure. Multivariable logistic regression analyses identified predictors of increased ER visits for renal colic. Results: There were 85,501 renal colic-related ER visits during the study period, involving 62,935 (74%) males and 22,566 (26%) females (p < 0.005). The mean ± standard deviation (SD) age of the males and females was 50 ± 5.8 and 48 ± 19.6 years, respectively (p = 0.1). Most of the ER arrivals were in the 31- to 50-year-old age group (37%, 31,508) (p = 0.02). The maximal ambient temperature (odds ratio (OR) = 2.213, 95% confidence interval (CI) = 2.148–2.279, p < 0.0001), lower heat index (i.e. low humidity; OR = 0.880, 95% CI = 0.872–0.887, p < 0.0001) and increased wind velocity (OR = 1.165, 95% CI = 1.149–1.182, p < 0.0001) had a significant linear effect on ER visits for renal colic events. Conclusion: Conditions that increase sweat evaporation during the hottest months, including a decreased heat index and increased wind velocity, correlated with more ER visits for renal colic events, probably due to dehydration associated with elevated sweat evaporation.