Associations of body fat and its changes over time with quality of life and prospective mortality in hemodialysis patients.
BACKGROUND
In maintenance hemodialysis (MHD) patients, a larger body size is associated with better survival but a worse self-reported quality of life (QoL). It is not clear whether muscle mass or body fat confers the survival advantage.


OBJECTIVE
We hypothesized that both a low baseline body fat percentage and a loss of fat over time were independently associated with higher mortality but with a better QoL score.


METHODS
In 535 adult MHD patients, body fat was measured directly with the use of near infrared interactance and QoL was measured with a Short Form 36 questionnaire. The patients were followed for < or =30 mo.


RESULTS
Across four 12% increments of body fat at baseline, the reported QoL scores were progressively lower (P < 0.01). After a multivariate adjustment for demographics and surrogates of muscle mass and inflammation (ie, midarm muscle circumference, serum creatinine, and proinflammatory cytokines), 46 patients with body fat of <12% had a death hazard ratio (HR) 4 times that of 199 patients with body fat content between 24% and 36% (HR: 4.01; 95% CI: 1.61, 9.99; P = 0.003). In 411 MHD patients whose body fat was remeasured after 6 mo, a fat loss (< or =-1%) was associated with a death risk 2 times that of patients who gained fat (> or =1%) after a multivariate adjustment (HR: 2.06; 95% CI: 1.05, 4.05; P = 0.04).


CONCLUSIONS
A low baseline body fat percentage and fat loss over time are independently associated with higher mortality in MHD patients even after adjustment for demographics and surrogates of muscle mass and inflammation, whereas a tendency toward a worse QoL is reported by MHD patients with a higher body fat percentage. Obesity management in dialysis patients may need reconsideration.
Division of Nephrology and Hypertension, Los Angeles Biomedical Institute at Harbor-UCLA Medical Center, Torrance, CA 90509-2910, USA. kamkal@ucla.edu
Kamyar
K
Kalantar-Zadeh
Noriko
N
Kuwae
Dennis Y
DY
Wu
Ronney S
RS
Shantouf
Denis
D
Fouque
Stefan D
SD
Anker
Gladys
G
Block
Joel D
JD
Kopple
D000273:Adipose Tissue / Q000378:metabolism / Q000502:physiology*; D000328:Adult; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D001824:Body Constitution / Q000502:physiology; D005260:Female; D005544:Forecasting; D006760:Hospitalization; D006801:Humans; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011788:Quality of Life; D006435:Renal Dialysis / Q000401:mortality*; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D011795:Surveys and Questionnaires; D015431:Weight Loss