People who have larger waistlines are twice at the risk of dying from kidney disease.
The study, led by a Loyola University Health System researcher, found that the larger a kidney patient's waist circumference, the greater the chance the patient would die.
Lead researcher Holly Kramer, MD, MPH, and colleagues showed that waist circumference was more strongly linked to mortality than another common measure of obesity, body mass index (BMI).
Researchers examined data from 5,805 adults aged 45 and older who had kidney disease and participated in a study called REGARDS (Reasons for Geographic and Racial Differences in Stroke).
They were followed for a median of four years and during that time 686 kidney patients (11.8 percent) died. The average BMI of the kidney disease patients who died was 29.2.
This was lower than the average BMI, 30.3, of the patients who survived. (A BMI between 25 and 29.9 is considered overweight, while a BMI of 30 and above is obese.)
By contrast, the kidney patients who died had a larger average waist circumference (40.1 inches) than the patients who survived (39.1 inches.)
Researchers compared kidney disease patients with large waists to patients who had more normal waist sizes.
After adjusting for BMI and other risk factors, women with waists equal to or greater than 42.5 inches and men with waists equal to or greater than 48 inches were 2.1 times more likely to die than those with trimmer waists (less than 31.5 inches for women and less than 37 inches for men).
Researchers concluded that in adults with kidney disease, BMI by itself may not be a useful measure to determine mortality risks associated with fat. The reason is that BMI reflects several components, including muscle mass and abdominal fat.
"In contrast, waist circumference reflects abdominal adiposity [fat] alone and may be a useful measure to determine mortality risk associated with obesity in adults with chronic kidney disease, especially when used in conjunction with BMI," the researchers concluded.
The study was published in the American Journal of Kidney Diseases.