From hurricanes to heat waves: How climate change negatively impacts patients with kidney failure

Shortly after nephrologist Sarah Young, MD, became the medical director of a dialysis unit in Aurora in 2005, she met a new patient — a 54-year-old man with type 2 diabetes who had started receiving dialysis a few months earlier. When she introduced herself to him, his response took her by surprise. 

“What is your plan if this dialysis unit has to shut down?” he asked her.  

What Young didn’t know yet was that the man had lost his home — and his dialysis center — in New Orleans, Louisiana, to Hurricane Katrina, forcing him to evacuate to Texas before he eventually moved to Colorado.  

“It was really anxiety-provoking to think about that challenge,” said Young, an associate professor of clinical practice in the Division of Renal Diseases and Hypertension at the University of Colorado Department of Medicine.  

Dialysis is a treatment for people whose kidneys do not function properly, typically due to having kidney failure, also called end-stage kidney disease. A dialysis treatment, often needed several times a week, replicates the kidney’s function by removing waste products and extra fluid from a person’s blood.  

“He was not the only dialysis patient who was adversely affected by Hurricane Katrina. End-stage kidney disease patients had increased hospitalizations, especially if they evacuated late and if they were socially isolated,” Young said. “And we had a real challenge finding places to provide dialysis to these patients across the country because we had a huge number of dialysis patients who had to evacuate Louisiana.”

Nearly 20 years later, as communities in Florida continue to grapple with the impacts of Hurricane Helene and Hurricane Milton, Young is raising awareness of how natural disasters fueled by climate change, also called climate disasters, affect patients with kidney disease — an issue she recently discussed in a Department of Medicine Grand Rounds presentation.  

“It’s too early for us to know the impact of these recent hurricanes on end-stage kidney disease patients, but we do know that large numbers of dialysis units had to close in states that were affected,” Young said. 

Previous studies of other climate disasters have shown the potential long-term effects. For example, there was a 21% decline in the number of kidney transplants that occurred in Louisiana in the subsequent year following Hurricane Katrina — a concerning trend given that transplants improve mortality in dialysis patients, Young explained, adding: “A lot of patients were left dependent on dialysis as a consequence of the storm.”

Subsequent studies have shown that, in the wake of a hurricane, dialysis patients have a higher mortality, meaning there is a higher percentage of deaths. One study, for instance, looked at patients living in counties that were affected by hurricanes between 1997 and 2017, and it found that mortality remained higher for 30 days after the storm. 

“Climate events, like these hurricanes, have been happening for more than two decades, and end-stage kidney disease patients are particularly vulnerable,” Young said. “Patients have been asking us to increase climate resilience in the kidney disease community for as long as I’ve been practicing.”  

It’s not just about hurricanes 

“As the planet warms, we are seeing more extreme weather events,” Young said. “That leads to very significant public health and social infrastructure impacts.”  

Although Colorado may not be at risk for hurricanes, it is not immune to the dangers of climate change, Young warned. 

“Here in Colorado, we need to worry about fire and heat,” Young said. 

Extreme heat due to climate change has been shown to have negative effects on people’s health. One study, for example, looked at heat-related mortality (deaths related to a person’s exposure to extreme heat) that could be attributed to climate change. It found that across the globe, 37% of deaths from heat-related mortality could be attributed directly to climate change. 

There are a variety of health outcomes from heat waves, including heatstroke, impacts on mental health, adverse pregnancy outcomes, exacerbations of respiratory and cardiovascular disease, and acute kidney injury. The people who are more at risk include the elderly, newborns, pregnant people, outdoor workers, people with chronic medical problems, Indigenous people, people who come from lower-income households, and socially marginalized groups. 

“Many of my patients who have chronic kidney disease and end-stage kidney disease have a lot of these risk factors,” Young said. 

In 2019, the first study on the association of extreme heat events with hospital admission or death among patients with end-stage kidney disease was published. The study — done in Philadelphia, Boston, and New York — found that end-stage kidney disease patients had an increased risk of same-day hospital admission and mortality rate during a heat wave. 

Previous studies have also shown that extreme heat events may lead to an increased risk of kidney stones, with people, particularly men, getting kidney stones within three days of the heat event. 

“One of the theories for why this is happening is because of urban heat islands. Because cities don’t have enough greenery, the temperature does not drop as much at night,” Young said, explaining this may contribute to urine becoming more concentrated and the formation of a kidney stone. “That has led people to believe that something called the ‘kidney stone belt’ will move with time.” 

The kidney stone belt refers to the southeast region of the U.S. where the prevalence of kidney stones is 50% higher than the rest of the country. “Because of rising temperatures, we anticipate that the kidney stone belt will move north and west,” she said. 

Poor air quality can also negatively affect people with kidney disease. Studies have shown exposure to particulate matter air pollution is associated with chronic kidney disease and end-stage kidney disease.

A disease health care professionals and researchers are continuing to investigate is called “chronic kidney disease of uncertain etiology” — a potentially deadly disease with unknown causes, but it appears to have a connection to hot environments. 

“We don’t know all the factors that contribute to this, but we know there are epidemics around the world of this disease. It’s occurring predominantly in agricultural workers who are in the hottest parts of their country and doing strenuous outdoor labor,” Young said.  

‘A vicious cycle’ 

The heat waves, extreme weather events, food insecurity, and change in infectious disease patterns that occur because of a warming climate lead to more people needing health care, Young explained. 

“We’re in a bit of a vicious cycle,” she said. “Because health care itself is a producer of greenhouse gas emissions.” 

On a global scale, 5.2% of global emissions are from the health care industry. In the U.S., an estimated 10% of greenhouse gas emissions are from the health care industry.  

“If the health care industry were a country, it would rank 13th in the world in terms of greenhouse gas emissions,” she said.  

Young suspects that dialysis is a large contributor to the U.S.’s carbon footprint, because the country provides dialysis to people “more than anybody else.” 

“We don’t know a lot about the environmental effects of dialysis. We do know that hemodialysis (a machine that filters blood to treat advanced kidney failure) is extremely water hungry,” Young said. “That’s because we have to use a reverse osmosis machine, which wastes a ton of water. Some of the most inefficient ones will waste 50% of the water that goes through the machine right down the drain.” 

Hemodialysis also leads to high rates of power usage and waste generation (such as hazardous waste and landfill), she added.  

What can be done? 

Health experts like Young are working to increase climate resilience and improve health outcomes for patients who depend on dialysis through a variety of methods, including raising awareness. 

For example, Laveen Khoshnaw, MD, an intern in the CU Internal Medicine Residency Program, wrote an article with Young and Richard Johnson, MD, on 10 tips for caring for chronic kidney disease patients during a heat wave. One of these tips is to make a heat action plan, where patients will strategize how they will stay cool and hydrated — as well as which medications they may need to adjust — in case there is extreme heat. 

Young is also starting a new project in collaboration with Sherri Cook, PhD, an associate professor in the CU Boulder College of Engineering and Applied Science, that aims to compare the carbon footprints of different dialysis modalities (hemodialysis, peritoneal dialysis, and home dialysis) under varying extreme climate scenarios. Through this research, Young hopes to learn which dialysis modality will best serve patients who are going through a natural disaster, such as a hurricane. 

“I’m finally getting back to that question my patient asked me almost 20 years ago about what my plan is if a dialysis unit shuts down,” she said. “Essentially, what that patient told me was that climate change is coming for all of us — but it’s not coming for all of us equally, and there are certain populations who are more vulnerable. 

“We need more research into vulnerable populations to help them adapt to these climate events. And we need to measure our own carbon footprint, so we know how to mitigate and reduce it.”