Being skinny is dangerous for dialysis patients

A new study has shown that dialysis patients with low body fat are at increased risk of death.

"Our study indicates that body fat may be protective in dialysis patients. The results add to the increasing number of reports about the 'obesity paradox' or 'reverse epidemiology' in patients with chronic kidney disease and other chronic diseases," said Kamyar Kalantar-Zadeh, PhD (LABioMed at Harbor-UCLA).

"Counter-intuitively, higher body mass index is associated with greater survival in hemodialysis patients. We hypothesized that very low body fat-less than ten percent-would be a strong predictor of mortality," Kalantar-Zadeh added.

For the study, researchers used near-infrared interactance technology to measure body fat percentage in 671 hemodialysis patients from eight California dialysis centers.

They then compared five-year mortality rates for patients at different levels of body fat percentage.

The mortality rate was highest for dialysis patients with less than 10% body fat-2.5 to 3 times higher than for those with body fat of 20% to 30%.

The increased risk of death for patients with very low body fat remained after adjustment for age, sex, race, other illnesses, and key laboratory results.

Further analyses using continuous values of body fat confirmed a direct, linear relationship between body fat and mortality risk.

"The higher the body fat, the greater the survival," said Kalantar-Zadeh.

The study has been presented at the American Society of Nephrology's 42nd Annual Meeting and Scientific Exposition in San Diego.