A study from researchers at the Perelman School of Medicine at the University of Pennsylvania found the risk of mortality is lower for patients with chronic kidney disease when they receive potassium supplements during hot temperature days.
Patients who received the additional potassium saw a 10% drop in mortality, researchers said in a Perelman press release.
Patients with CKD on diuretics are often at risk for low potassium levels, or hypokalemia. That condition can increase the risk of death from cardiac arrhythmias or other causes. While some patients are prescribed combination diuretics that contain both a thiazide and potassium-sparing diuretic, nephrologists and other clinical staff may not be aware that sweating can increase the risk of potassium loss in warmer weather, according to the press release.
“We already know that hot outdoor temperatures are associated with increased risk of heat stroke, dehydration, heart disease, respiratory diseases and higher risk of death overall, but people who take furosemide and have insufficient intake of potassium are at increased risk,” Sean Hennessy, PharmD, PhD, a professor of epidemiology and systems pharmacology and translational therapeutics at Perelman and senior author, said in the release. “As outside temperatures increase, the apparent survival benefit of potassium also increases.”
Nephrologists often prescribe the drug furosemide, a diuretic known commonly as Lasix, to decrease fluid retention and combat swelling in the arms, legs and/or abdomen in patients with heart failure, high blood pressure, and/or kidney and liver disease. The drug, like many other diuretics, causes patients to urinate more than normal, leading to lower levels of potassium in the body. These lower levels can be more dangerous when outdoor temperatures are high, as patients often lose additional potassium through sweating, the release noted.
Researchers for the study looked at 1999 to 2010 data from Medicaid patients in California, Florida, New York, Ohio and Pennsylvania. The data set represented about 40% of total U.S. Medicaid enrollees and made up approximately 20% of the total U.S. population, according to the release. Data were included from those who took furosemide at 40 mg/day or more and had not been prescribed any furosemide nor diagnosed with hypokalemia in the previous year.
Among the 337,885 people who took 40 mg/day or more of furosemide, 32% of them also took potassium when starting the diuretic. The team linked these data to zip code-level daily temperature data from the National Oceanic and Atmospheric Administration and compared two groups — one group included patients who took prescription potassium to prevent hypokalemia when beginning furosemide, and the other included patients who did not take prescription potassium when taking furosemide. The team found that across all temperatures, the potassium-taking group experienced a 9.3% lower risk of death than the group who did not take potassium. This survival benefit was also higher when daily maximum temperatures were higher.
“If this potential relationship between temperature and the survival benefit of empiric potassium is true, it would have important clinical and public health implications,” the authors wrote. “It is well established that high outdoor temperature is associated with increase in mortality and morbidity. Some excess deaths in furosemide users, especially among socioeconomically disadvantaged populations such as Medicaid enrollees in the USA, might be avoidable through interventions to increase potassium intake on hot days. The number of lives saved by such interventions would be expected to increase as global climate change continues.”
The authors speculated that patients with CKD who reside in warmer regions might tolerate increases in temperature better than those in cooler regions.
Young Hee Nam
“Also, a temperature–potassium interaction on mortality, if it exists, might differ across subgroups, such as geographic regions, sociodemographic characteristics including age, comorbidities or degree of frailty. Because we were unable to explore such relationships given the limited number of high-temperature deaths, further research is warranted to investigate these potential relationships in diverse subgroups and health outcomes,” they said.
Lead author Young Hee Nam, PhD, a post-doctoral researcher in biostatistics, epidemiology and informatics, said the study results “do not imply that more potassium is better, and do not imply that prescription potassium may be beneficial for all patients. Further studies are needed to find out the generalizability of our findings to other patient populations. The best way to reduce harmful effects of high temperatures on mortality might be to avoid exposure to high temperatures if possible.” – by Mark E. Neumann
Disclosures: This work was supported by the U.S. National Institute on Aging (R01AG025152) and the U.S. National Institute of Diabetes and Digestive and Kidney Diseases (R01DK102694). The authors report no relevant financial disclosures.