Muscle Mass, Fat, and Mortality in Hemodialysis Patients

A group of investigators led by Sho Kojima examined the associations among muscle mass, intramuscular fat, and abdominal fat measured by abdominal computed tomography (CT) and mortality in hemodialysis patients. High body mass in this population is associated with low mortality, while abdominal obesity is associated with increased mortality.

The team conducted a two-center, retrospective cohort study of hemodialysis patients who had abdominal CT between January 2013 and December 2018. Researchers used CT images at the third lumbar vertebral level to measure skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and the ratio of visceral fat to subcutaneous fat (VSR). They used the multivariate Cox proportional hazards model to determine independent predictors of all-cause, cardiovascular, and noncardiovascular mortality.

Of the 344 patients in the study (median age, 71.0 years; 33.7% female), 145 died during a median follow-up of 4.9 years (46 from cardiovascular causes, 99 from noncardiovascular causes). Lower MRA (HR, 0.71; 95% CI, 0.58-0.87; P=.001) and higher VSR (HR, 1.17; 95% CI, 1.01-1.37; P=.04) were independently associated with higher all-cause mortality but were not associated with lower SMI (HR, 0.87; 95% CI, 0.68-1.11; P=.26). Lower MRA (HR, 0.51; 95% CI, 0.35-0.73; P<.001) and higher VSR (HR, 1.29; 95% CI, 1.09-1.54; P=.003) were also associated with cardiovascular and noncardiovascular mortality, respectively.

The researchers concluded that intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Source: Nephrology Dialysis Transplantation