1. Body Composition and All-Cause Mortality in Hemodialysis Patients
Cindy Huang1, Hocine Tighiouart1, Srinivasan Beddhu2, Alfred Cheung2, Johanna Dwyer1, Garabed Eknoyan3, Gerald Beck4, Andrew Levey1, Mark Sarnak1
1 Tufts Medical Center, Boston, MA; 2 Univ. of Utah, Salt Lake City, UT; 3Baylor College of Medicine, Houston, TX; 4Cleveland Clinic, Cleveland, OH
Background
Results
Results
Results
Figure 1. Association between MAMC, triceps skinfold and BMI with all-cause mortality in unadjusted and adjusted models*
Obesity is associated with increased mortality in the general population, but higher body mass index (BMI) is associated with decreased mortality in hemodialysis patients. The reason for the latter finding is unknown
BMI does not differentiate between fat mass and muscle mass
Fat mass and muscle mass may have different effects on all-cause mortality in HD patients
No large study has examined the contribution of individual body composition components to all-cause mortality in HD patients
Table 1. Patient characteristics by triceps quartiles
Table 3. Measures of body composition and their association with all-cause mortality in continuous analyses
Overall
(n=1709)
Triceps Q1 (n=427)
triceps Q2 (n=430)
triceps Q3 (n=422)
triceps Q4 (n=430) p
Age (yrs)
58 (14)
54 (16)
59 (14)
59 (12)
<0.001
Women 56 26 45 71 80
Blacks 64 60 68 69
0.002 DM 44 22 41 53
CVD 20 17 23
0.06
PVD 16 14 18
0.36
IHD 39 33 43
0.01
CHF 40 42 37
0.44
BMI (kg/m2)
25.2 (5.1)
21.5 (3.0)
23.9 (3.5)
26.0 (4.4)
29.6 (5.1)
Triceps (mm)
16.3 (7.9)
7.1 (1.8)
12.6 (1.5)
18.2 (1.8)
27.4 (4.2)
MAMC (cm)
24.8 (3.8)
24.1 (3.9)
24.4 (3.6)
25.0 (3.8)
25.7 (3.9)
Labs
Cr (mg/dl)
10.3 (2.9)
10.9 (3.3)
10.3 (2.7)
10.1 (2.5)
9.9 (2.5)
Albumin (g/dl)
3.6 (0.4)
3.7 (0.4)
3.6 (0.3)
0.86
Ca (mg/dl)
9.3 (1.0)
9.2 (0.9)
0.47
Phos (mg/dl)
5.8 (1.9)
5.8 (2.1)
5.6 (1.8)
5.9 (1.6)
0.19
HD-related
Vintage (yrs)
3.7 (4.4)
4.8 (5.3)
3.8 (4.3)
3.5 (4.0)
2.8 (3.4)
Unadjusted model
Adjusted model* HR
95%CI
BMI (per SD)
0.92
0.89
Triceps (per SD)
0.93
0.85
MAMC (per SD)
0.86
Demographics
Comorbid Conditions
*Adjusted for age, sex, race, vintage, creatinine, albumin, PVD, ischemic heart disease, CHF, other heart disease, diabetes, SBP, dialysis treatment
Additional Analyses
No changes in the importance of triceps skinfold and MAMC if they were included in the same model
Adjusting for height did not significantly change the results
Interactions were not significant (p>0.2)
Triceps skinfold and MAMC
Triceps skinfold and sex
MAMC and sex
Anthropometric measurements
Methods
HEMO study
Prospective, randomized, multicenter clinical trial
Standard dose (Kt/V 1.05) vs high dose (Kt/V 1.45)
High-flux membrane vs low-flux membrane
Body composition measurements
BMI
Fat mass: triceps skinfold
Muscle mass: Mid-arm muscle circumference (MAMC)
MAMC (cm)=mid-upper arm circumference-π*triceps skinfold (cm)
Outcome variable
All-cause mortality
Functional forms of BMI, triceps skinfold and MAMC with all-cause mortality using restricted cubic splines
Univariate and multivariate Cox regression
Additional analyses
Triceps skinfold and MAMC in the same model
Triceps skinfold and MAMC adjusted for height given that BMI takes into account height
Interactions
Triceps skinfold and MAMC
Triceps skinfold and sex
MAMC and sex
Table 2. Body composition quartiles and their association with for all-cause mortality
Unadjusted model
Adjusted model* HR
95%CI
BMI
P#=0.022
P#<0.001 Q1
reference
Reference Q2
0.91
0.78 Q3
0.87 Q4
0.79
0.66
Triceps
P#=0.13
0.97
0.72
0.95
0.73
0.58
MAMC
0.68
0.62
0.69
0.60
Conclusion
Data are presented as mean (SD) or %
Both high muscle and fat mass are associated with lower all-cause mortality in HD patients
Individual decision making is recommended regarding weight loss in obese hemodialysis patients
Nutritional interventions are required for patients with low BMI, MAMC and body fat
Clinical trials to increase muscle mass and body fat in cachectic HD patients should be considered
Median length of follow-up: 2.5 years
Total number of deaths: n=783
Pearson correlation coefficients were:
0.62 between triceps skinfold and BMI
0.63 between MAMC and BMI
0.17 between triceps skinfold and MAMC
#: p values are for trend across quartiles
This project was supported by NIH T32 DK07777 and K24 DK grants