[Sportschosun Jang Jong-ho] Summer is a season when the risk of kidney disease rises because of intense heat and dehydration.
In Korea, chronic kidney disease, or CKD, affects a significant number of people, making kidney health management especially important during hot weather. Korea is one of the countries with the highest prevalence of chronic kidney disease in the world. Annual medical costs related to the disease also exceeded 283 billion won in 2024, ranking third among single diseases. The National Institute of Health and the Korean Society of Nephrology recently announced that Korean patients with chronic kidney disease face about 1.66 times higher risk of worsening kidney function than patients in the U.S. CRIC cohort, and are more likely to progress to end-stage renal failure.
Lee Ji-yeon, head of nephrology at Gangnam Bedro Hospital, explained, "For patients with chronic kidney disease, seasonal risk factors can overlap, making it even more likely that kidney function will decline in the summer."
◇One in seven to eight people has chronic kidney disease... There are no early symptoms even when kidney function declines
The kidneys, also called the renal organs, are major organs that help maintain a stable internal environment. Their main role is to filter waste from the body and cleanse the blood through millions of tiny glomerular structures made up of capillaries. They also help regulate body fluids, electrolytes, and hormones, maintaining homeostasis. If kidney function declines continuously for more than three months, or if damage is confirmed, a diagnosis of chronic kidney disease is made.
Chronic kidney disease affects one in seven to eight people in Korea, and its prevalence is also rising worldwide as populations age. Depending on the degree of kidney function decline, the disease is classified from stage 1, which is close to normal, to stage 5, when dialysis must be considered. The higher the stage, the greater the likelihood of complications such as cardiovascular disease. If the disease progresses to end-stage renal failure, the prognosis is often poor and the mortality rate rises sharply.
The problem is that most patients do not notice any symptoms at an early stage, even when kidney function has declined. Lee Ji-yeon said, "Most patients do not realize their kidney function is worsening until proteinuria is detected through urine tests or abnormal findings appear on imaging studies."
However, only about 5 to 7 percent of chronic kidney disease patients actually experience a meaningful decline in kidney function, and the severity and level of treatment vary greatly depending on the stage and condition of the patient. That is why it is important to detect the disease early and prevent it from worsening through consistent management. Diabetes and hypertension are considered major causes of chronic kidney disease, so extra caution is needed if those conditions are present.
◇Reduce potassium intake in summer and maintain an appropriate level of fluid intake for each individual
What chronic kidney disease patients should pay particular attention to is kidney health management in summer. Extreme heat itself places a burden on the kidneys of patients with chronic kidney disease. Excessive heat can cause dehydration and electrolyte imbalance, and the risk may increase further when combined with the effects of medications such as diuretics.
Lee Ji-yeon explained, "Heat waves can reduce renal blood flow through dehydration, which increases the risk of acute kidney injury and can worsen chronic kidney disease symptoms. In fact, a meta-analysis has reported that in high-temperature environments, the risk of kidney disease, related hospitalizations, and emergency room visits rises by about 30 percent."
A bigger problem is summer eating habits. In particular, summer fruits such as Korean melon, watermelon, and bananas are high in potassium, so intake must be carefully controlled because they can burden the kidneys and raise the risk of hyperkalemia. It is also advisable to avoid excessive consumption of juice and sports drinks. High salt intake of more than 5 grams a day, as well as caffeinated and alcoholic beverages, should also be avoided.
Proper fluid intake based on kidney function and disease status is also important. In summer, people tend to sweat more and drink more water than usual to quench their thirst, but chronic kidney disease patients should be careful because excessive fluid intake can instead strain the kidneys. Rather than drinking a large amount at once, it is recommended to drink smaller amounts several times over time. The KDCA's heatwave preparedness guidelines for vulnerable groups, released in early July, also stress that kidney disease patients should maintain an appropriate individual level of fluid intake.
If symptoms such as persistent dehydration, changes in urine volume or color, or extreme fatigue appear, it is better not to dismiss them as simple heat exhaustion and instead consult a specialist.
Lee Ji-yeon advised, "For chronic kidney disease patients, the risk of dehydration and worsening kidney function in summer must be watched especially closely. Rather than simply drinking water or relying on health foods, patients need to consult medical staff and manage their condition carefully based on their own kidney function and disease status."
Jang Jong-ho, bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
