VOLUME 17 NUMBER 12 | dEcEMBER 2009 | www.obesityjournal.org
nature publishing group
Obesity is a serious health care issue worldwide. In the United
States, more than one half of all adults are overweight and
obesity ranks second to smoking as a cause of preventable
death. African Americans, particularly black women, tend to
have a higher prevalence of obesity when compared to other
various racial and ethnic groups (1). There is evidence that
obesity is associated with loss of kidney function (2–4), and
one study concluded that a high BMI is potentially a modifiable
risk factor for End-Stage Renal Disease (ESRD) (3). In addi-
tion, incident dialysis patients with a family history of ESRD
are reported to have a higher prevalence of obesity, and older
adults with a first degree relative with ESRD are more obese
than others (5). African Americans have a higher incidence of
kidney failure and disproportionally comprise up to 30% of the
ESRD population. It is uncertain whether obesity contributes
to racial differences in risk of ESRD; and, thus, the first aim
of this study is to examine whether obesity is associated with
racial differences in the risk for progression to ESRD.
There are reports suggesting a paradoxical association with
obesity and improved survival in the ESRD and heart fail-
ure populations (6,7). It has also been reported that African
Americans with ESRD survive longer than whites despite hav-
ing a higher burden of cardiovascular disease (CVD) (8,9).
Until recently it was not known if the same racial survival
benefit applied to a pre-ESRD population or to other CVD
populations as well. We recently reported that elderly African-
American patients with more severe chronic kidney disease
(CKD) and incident acute myocardial infarction (AMI) expe-
rienced better survival (8,10). Thus, our second aim is to exam-
ine the impact of obesity on survival among this same elderly
cohort with CVD and to determine if the effect of obesity on
survival differed among whites and African Americans.
Methods and Procedures
We analyzed data from the Cooperative Cardiovascular Project, which
features data from 234,754 Medicare patients seen at 6,684 hospitals
Obesity, End-stage Renal disease,
and Survival in an Elderly cohort With
Janice P. Lea1, Daryl O. Crenshaw1, Stephen J. Onufrak2, Britt B. Newsome2,3 and William M. McClellan4
Obesity is highly prevalent in African Americans and is associated with increased risk of End-Stage Renal Disease
(ESRD) and death. It is not known if the effect of obesity is similar among blacks and whites. The aim of this study
is to examine racial differences in the association of obesity with ESRD and survival in elderly patients (age >65).
Data were obtained for 74,167 Medicare patients with acute myocardial infarction (AMI) between February 1994 and
July 1995. BMI was calculated as weight (kg) divided by height (m2). We evaluated the association of BMI class with
ESRD incidence and death using multivariable Cox proportional hazards models, testing for race-BMI interactions.
Compared to whites, African Americans had higher BMI (26.9 vs. 26.0, P < 0.0001) and estimated glomerular filtration
rate (72.4 ml/min/1.73 m2 vs. 66.6 ml/min/1.73 m2, P < 0.0001). Crude ESRD rates increased with increasing obesity
among whites but not among blacks. However, after adjusting for age, sex, and other comorbidities, obesity was
not associated with increased ESRD rate among blacks or whites and the interaction between race and BMI was
not significant. Furthermore, for both races, patients classified as overweight, class 1 obese, or class 2 obese had
similar, significantly better survival abilities compared to normal weight patients and the race BMI interaction was
not significant. In conclusion, obesity does not increase risk of ESRD among black or white elderly subjects with
cardiovascular disease (CVD). However, both obese blacks and whites, in this population, experience a survival
benefit. Further studies need to explore this obesity paradox.
Obesity (2009) 17, 2216–2222. doi:10.1038/oby.2009.70
1Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA; 2Agricultural Research Service, US Department of Agriculture, Stoneville,
Mississippi, USA; 3Department of Medicine, University of Alabama School of Medicine, Birmingham, Alabama, USA; 4Department of Public Health, Emory University
School of Medicine, Atlanta, Georgia, USA. Correspondence: Janice P. Lea (email@example.com)
Received 6 February 2008; accepted 23 February 2009; published online 26 March 2009. doi:10.1038/oby.2009.70
VOLUME 17 NUMBER 12 | dEcEMBER 2009 | www.obesityjournal.org
10. Newsome BB, McClellan WM, Coffey CS et al. Survival advantage of black
patients with kidney disease after acute myocardial infarction. Clin J Am Soc
11. Marciniak TA, Ellerbeck EF, Radford MJ et al. Improving the quality of care
for Medicare patients with acute myocardial infarction: results from the
Cooperative Cardiovascular Project. [see comment]. JAMA 1998;279:
12. International Classification of Diseases, Ninth Revision, Clinical Modification.
Public Health Service, US Department of Health and Human Services:
Washington, DC, 1997.
13. Levey AS, Bosch JP, Lewis JB et al. A more accurate method to estimate
glomerular filtration rate from serum creatinine: a new prediction equation.
Modification of Diet in Renal Disease Study Group. Ann Intern Med
14. National Kidney Foundation. K/DOQI clinical practice guidelines for chronic
kidney disease: evaluation, classification and stratification. Am J Kidney Dis
2002;39(2 Suppl 1):S1–S266.
15. Allison JJ, Kiefe CI, Weissman NW et al. Relationship of hospital teaching
status with quality of care and mortality for Medicare patients with acute MI.
16. Overweight, obesity, and health risk. National Task Force on the Prevention
and Treatment of Obesity. Arch Intern Med 2000;160:898–904.
17. Ohkawa S, Odamaki M, Ikegaya N et al. Association of age with muscle
mass, fat mass and fat distribution in non-diabetic haemodialysis patients.
Nephrol Dial Transplant 2005;20:945–951.
18. Mitch WE, Maroni BJ. Factors causing malnutrition in patients with chronic
uremia. Am J Kidney Dis 1999;33:176–179.
19. Kalantar-Zadeh K, Kopple JD, Kilpatrick RD et al. Association of
morbid obesity and weight change over time with cardiovascular
survival in hemodialysis population. Am J Kidney Dis 2005;46:
20. Flegal KM, Graubard BI, Williamson DF, Gail MH. Cause-specific excess
deaths associated with underweight, overweight, and obesity. JAMA
21. Elsayed EF, Tighiouart H, Weiner DE et al. Waist-to-hip ratio and body mass
index as risk factors for cardiovascular events in CKD. Am J Kidney Dis
22. Johansen KL, Young B, Kaysen GA, Chertow GM. Association of body
size with outcomes among patients beginning dialysis. Am J Clin Nutr