Heat Exposure Linked to Higher CKD & ESKD Rates, Especially in Underserved Areas

The increasing frequency and intensity of heat waves are emerging as a significant, and potentially underestimated, risk factor for kidney disease. Latest research published in the Clinical Journal of the American Society of Nephrology indicates a clear association between exposure to higher temperatures and both the prevalence of chronic kidney disease (CKD) and the incidence of end-stage kidney disease (ESKD). The study, led by Rajiv Saran, MD, MBBS, MS, DTCD, MRCP (UK), at the University of Michigan Medical School, adds to a growing body of evidence highlighting the vulnerability of kidney health to climate change. Wang F, et al. Clin J Am Soc Nephrol. 2026

Heat and Kidney Health: A Growing Concern

While the immediate effects of extreme heat – dehydration, heat exhaustion, and acute kidney injury – are well-documented, this study focuses on the long-term consequences of sustained temperature increases. Researchers analyzed data from over 3,000 U.S. Counties, combining kidney disease surveillance data with historical temperature records. The findings reveal a statistically significant link: for every 1°C increase in average annual temperature, there was a 0.23 percentage point increase in CKD prevalence and a 1.37 increase in ESKD cases per 100,000 population.

The kidneys play a crucial role in regulating fluid balance and filtering waste products from the blood. Heat stress can strain these functions, leading to inflammation and damage over time. Dehydration, a common consequence of heat exposure, further concentrates waste products and increases the workload on the kidneys. Extreme heat exposure has already been linked to increased emergency department visits and outpatient care among individuals with existing CKD, suggesting a direct pathway between temperature and kidney function.

Disproportionate Impact on Vulnerable Communities

The study’s findings too reveal a concerning disparity: the association between heat exposure and kidney disease was significantly stronger in high-poverty and nonmetropolitan areas. This suggests that socioeconomic factors and geographic location play a critical role in vulnerability. Individuals in these communities may have limited access to resources like air conditioning, adequate hydration, and timely medical care, exacerbating the effects of heat stress. The beta coefficient for high-poverty areas was 0.35 compared to 0.09 in low-poverty areas for CKD prevalence, and 1.5 versus 0.64 for ESKD incidence. Similar disparities were observed between nonmetropolitan and metropolitan counties.

This disparity underscores the importance of addressing social determinants of health in the context of climate change. Public health interventions aimed at mitigating the effects of heat must prioritize vulnerable populations and ensure equitable access to resources.

Study Details and Limitations

The researchers utilized data from the CDC’s Kidney Disease Surveillance System (2005-2019) and the United States Renal Data System (2010-2019), alongside temperature data from the U.S. National Centers for Environmental Information. The study employed a county-level analysis, allowing for broad geographic coverage and the examination of regional variations. However, it’s important to note that this is an observational study, meaning it cannot definitively prove causation. Correlation does not equal causation. While the data demonstrate a strong association between heat exposure and kidney disease, other factors could be contributing to the observed relationship.

the study relies on Medicare data, which primarily covers individuals aged 65 and older. The findings may not be generalizable to younger populations. The researchers acknowledge the require for further investigation to understand the underlying mechanisms linking heat exposure and kidney health, and to identify effective strategies for prevention and mitigation.

What Does This Mean for Kidney Health?

The findings reinforce the growing recognition of climate change as a significant threat to public health, with the kidneys emerging as a particularly vulnerable organ system. The study highlights the need for proactive measures to protect kidney health in a warming world. This includes public health campaigns promoting hydration and heat avoidance, as well as policies aimed at reducing greenhouse gas emissions and mitigating the effects of climate change.

Joseph A. Vassalotti, MD, clinical professor at the Icahn School of Medicine at Mount Sinai and chief medical officer at the National Kidney Foundation, notes that the study “confirms that at a population level, heat exposure is associated with adverse kidney outcomes.” He emphasizes the need for further research on interventions to mitigate these effects, such as educating patients about staying hydrated and adjusting medication regimens during heat waves. U.S. Embassy Beirut

The Public Health Response and Future Directions

Public health agencies are increasingly recognizing the need to address the health impacts of climate change, including the risks associated with extreme heat. Surveillance systems are being enhanced to track heat-related illnesses, and early warning systems are being developed to alert communities to impending heat waves. The CDC and other organizations provide guidance on protecting oneself from heat stress, including staying hydrated, seeking shade, and avoiding strenuous activity during peak hours.

Looking ahead, further research is needed to identify individuals at highest risk for heat-related kidney disease and to develop targeted interventions. This includes investigating the role of genetic predisposition, pre-existing health conditions, and socioeconomic factors. Research is needed to evaluate the effectiveness of different mitigation strategies, such as cooling centers, urban greening initiatives, and changes in building codes. The National Kidney Foundation is actively involved in raising awareness about the link between climate change and kidney health, and advocating for policies that protect vulnerable populations.

The findings of this study serve as a critical reminder that protecting kidney health requires a comprehensive approach that addresses both individual risk factors and the broader environmental challenges posed by climate change.