Lean Body Mass and Survival in Hemodialysis Patients and the Roles of Race and Ethnicity.
BACKGROUND
Lean body mass (LBM) represents the "fat-free" muscle mass in hemodialysis (HD) patients and is an important nutritional measure. Previous studies have found that both higher LBM and body mass index (BMI) were related to greater survival in HD patients. Additional studies have shown differences in survival across racial-ethnic groups of HD patients. However, the association of LBM and mortality across racial-ethnic subgroups has not been examined.


OBJECTIVE
We hypothesize that racial differences in LBM affect the mortality in HD patients.


METHODS
Chronic HD patients from a large dialysis organization in the United States.


METHODS
Estimated LBM (eLBM), self-identified racial subgroups.


METHODS
5-year survival.


METHODS
We examined the association between baseline eLBM and survival using Cox proportional hazard models adjusted for demographics, comorbidities, and laboratory measures. Associations were examined across subgroups of race-ethnicity (non-Hispanic white, African American, and Hispanic) and BMI.


RESULTS
The final cohort included 117,683 HD patients, who were 62 ± 15 (mean ± standard deviation) years old, 43% women and 59% with diabetes mellitus. Higher eLBM was linearly associated with lower mortality. Compared with the reference group (48.4-<50.5 kg), patients with the lowest eLBM (<41.3 kg) had a 1.4-fold higher risk of mortality (hazard ratio: 1.37; 95% confidence interval: 1.30-1.44) in the fully adjusted model. A similar linear association was seen among patients with BMI < 35 kg/m(2) and in non-Hispanic whites and African American subgroups. However, higher eLBM was not associated with improved survival in Hispanic patients or patients with BMI ≥ 35 kg/m(2).


CONCLUSIONS
Potential residual confounding.


CONCLUSIONS
Higher eLBM is associated with a lower mortality risk in HD patients, especially among non-Hispanic white and African American groups. Hispanic patients do not demonstrate a similar inverse relationship. The association between LBM and mortality among different racial groups of HD patients deserves additional study.
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California; Division of Nephrology, Tianjin Union Medical Center, Tianjin, China.
Jialin
J
Wang
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California.
Elani
E
Streja
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California.
Connie M
CM
Rhee
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California.
Melissa
M
Soohoo
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California; Division of Nephrology, Jiangmen Central Hospital, Guangdong, China.
Mingliang
M
Feng
DaVita Clinical Research, Minneapolis, Minnesota.
Steven M
SM
Brunelli
Nephrology Section, Memphis Veterans Affairs Medical Center, Memphis, Tennessee; Division of Nephrology, University of Tennessee Health Science Center, Memphis, Tennessee.
Csaba P
CP
Kovesdy
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California; Department of Statistics, University of California Irvine, Irvine, California.
Daniel
D
Gillen
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California; Department of Medicine, Long Beach Veteran Affairs Health System, Long Beach, California. Electronic address: kkz@uci.edu.
Kamyar
K
Kalantar-Zadeh
School of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, Orange, California; Department of Medicine, Long Beach Veteran Affairs Health System, Long Beach, California. Electronic address: Joline.chen@va.gov.
Joline L T
JL
Chen
D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015992:Body Mass Index; D005006:Ethnicity; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000208:ethnology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D044469:Racial Groups; D006435:Renal Dialysis / Q000401:mortality*; D012680:Sensitivity and Specificity; D014481:United States