Elevated Ambient Temperature Associated With Increased Cardiovascular Disease–Risk Among Patients on Hemodialysis

Introduction

In many parts of the world, ambient temperatures have increased due to climate change. Due to loss of renal function, which impacts the regulation of thermoregulatory mechanisms, the ability to adapt and to be resilient to changing conditions is particularly concerning among individuals with kidney failure. The aim of this study was to assess the effect of heat on mortality and health care utilization among US patients on hemodialysis.

Methods

We conducted a retrospective analysis from 2011 to 2016 in the contiguous United States during warmer months among eligible patients on dialysis who were identified in the United States Renal Data System (USRDS). Daily ambient temperature was estimated on a 1 km grid and assigned to ZIP-code. Case-crossover design with conditional Poisson models were used to assess the risk of developing adverse health outcomes associated with temperature exposure.

Results

Overall, exposure to high temperature is associated with elevated risk for both mortality and health care utilization among hemodialysis patients. The risk ratios for all-cause mortality and daily temperature were 1.07 (95% confidence interval [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 (ED) visits, comparing 99th percentile versus 50th percentile daily temperatures. Larger effects were observed for cumulative lagged exposure 3 days prior to the outcome and for Southwest and Northwest climate regions.

Conclusion

Heat exposure is associated with elevated risk for cardiovascular disease (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.