Diagnosing Obesity by Body Mass Index in Chronic Kidney Disease
- 1 November 2010
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Hypertension
- Vol. 56 (5), 893-900
- https://doi.org/10.1161/hypertensionaha.110.160747
Abstract
Although obesity is associated with poor outcomes, among patients with chronic kidney disease (CKD), obesity is related to improved survival. These results may be related to poor diagnostic performance of body mass index (BMI) in assessing body fat content. Accordingly, among 77 patients with CKD and 20 controls, body fat percentage was estimated by air displacement plethysmography (ADP), skinfold thickness, and body impedance analysis. Defined by BMI ≥30 kg/m 2 , the prevalence of obesity was 20% in controls and 65% in patients with CKD. Defined by ADP, the prevalence increased to 60% among controls and to 90% among patients with CKD. Although sensitivity and positive predictive value of BMI to diagnose obesity were 100%, specificity was 72%, but the negative predictive value was only 30%. BMI correctly classified adiposity in 75%. Regardless of the presence or absence of CKD, subclinical obesity (defined as BMI 2 but excess body fat by ADP) was often missed in people with low lean body mass. The adjusted odds ratio for subclinical obesity per 1 kg of reduced lean body mass by ADP was 1.14 (95% CI: 1.06 to 1.23; P <0.001). Skinfold thickness measurements correctly classified 94% of CKD patients, but bioelectrical impedance analyzer–assessed body fat estimation did so in only 65%. Air displacement plethysmography–, skinfold thickness–, and bioelectrical impedance analyzer–assessed body fat all provided reproducible estimates of adiposity. Skinfold thickness measurements may be a better test to classify obesity among those with CKD. Given the low negative predictive value of BMI for obesity, our study may provide an explanation of the “obesity paradox.”Keywords
This publication has 13 references indexed in Scilit:
- Diagnostic performance of body mass index to detect obesity in patients with coronary artery diseaseEuropean Heart Journal, 2007
- Paradoxical Association Between Body Mass Index and Mortality in Men With CKD Not Yet on DialysisAmerican Journal of Kidney Diseases, 2007
- Prevalence of Overweight and Obesity in the United States, 1999-2004JAMA, 2006
- Survival advantages of obesity in dialysis patientsThe American Journal of Clinical Nutrition, 2005
- Development of bioelectrical impedance analysis prediction equations for body composition with the use of a multicomponent model for use in epidemiologic surveysThe American Journal of Clinical Nutrition, 2003
- Body-composition assessment via air-displacement plethysmography in adults and children: a reviewThe American Journal of Clinical Nutrition, 2002
- Differences in skeletal muscle and bone mineral mass between black and white females and their relevance to estimates of body compositionThe American Journal of Clinical Nutrition, 1992
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986
- Density of lean body mass is greater in blacks than in whitesJournal of Applied Physiology, 1984
- Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 YearsBritish Journal of Nutrition, 1974