Elevated Ambient Temperature Associated With Increased Cardiovascular Disease–Risk Among Patients on Hemodialysis
Background: Ambient temperatures have increased due to climate change in many parts of the world. Adaptation and resilience to changing conditions is particularly concerning among individuals with kidney failure, due to loss of renal function which impacts regulation of thermoregulatory mechanisms. The aim of this study is to assess the effect of heat on mortality and health care utilization among US hemodialysis patients.
Methods: We conducted a retrospective time-series analysis (2011-2016) of daily mortality, hospital admission, and emergency department visits identified in the United States Renal Data System. Daily ambient temperature was estimated on a 1 km grid and assigned to ZIP-code. Conditional-Poisson models were used to assess the risk of developing adverse health outcomes associated with temperature exposure.
Results: Overall, daily ambient temperature increase is associated with elevated risk for both mortality and health care utilization among hemodialysis patients. The rate ratios for all-cause mortality and daily temperature were 1.07 (95% CI: 1.03-1.11), 1.17 (1.14-1.21) for fluid disorder-related hospital admissions, and 1.19 (1.16-1.22) for cardiovascular event-related emergency department visits, comparing 99th percentile vs. 50th percentile daily temperatures. Larger effects were observed for cumulative lagged exposure three-days prior to the outcome and for Southwest and Northwest climate regions.
Conclusions: Heat exposure is associated with elevated risk for CVD-related mortality and health care utilization among this vulnerable population. Furthermore, the effect appears to be potentially cumulative in the short-term, and varies geographically.