Abstract 10882: Scaling to Lean Body Mass Accurately Classifies Abnormal LV Mass in Obese Children
Introduction: Scaling LV mass to BSA or height leads to inaccuracies in the diagnosis of LV hypertrophy in the obese pediatric population. Lean body mass (LBM) is free of the scaling biases seen with BSA and height. Our objectives were to 1) validate predictive equations for LBM, 2) determine the ideal scaling variable for LV mass, and 3) compare the diagnostic accuracy of predicted LBM (LBMp), BSA, and height in detecting abnormal LV mass in obese children.
Methods: Obese subjects ages 4 to 21 were recruited prospectively. Height, weight, sex, race and body mass index z-score were used to calculate LBMp. LV mass was measured by echocardiography. Dual-energy X-ray absorptiometry was used to measure LBM (LBMm). Bland-Altman plots were used to assess agreement between LBMp and LBMm. Linear regression was performed to assess the ideal scaling variable for LV mass. Centile curves of LV mass vs. LBMm as the reference-standard were compared with curves derived from LBMp, BSA, and height2.7 to assess their accuracy in detecting elevated LV mass.
Results: 309 subjects were enrolled for predictive equation validation, 195 had echocardiography performed. Mean age was 11.8 ± 3.4 years. The mean difference between LBMp and LBMm was 1.5% (95% limits of agreement: -16.5%, 19.4%). LBMm had the strongest relationship with LV mass (R2 = 0.83, p < 0.01) compared to LBMp (R2 = 0.81, p < 0.01), BSA (R2 = 0.77, p < 0.01), and height2.7 (R2 = 0.67, p < 0.01). Of the clinically derived variables, LBMp was the only measure to retain a relationship with LV mass upon multivariable regression (partial r = 0.89). LBMp was the most accurate scaling variable in detecting LV hypertrophy (PPV = 85.7%, NPV = 99.3%) compared to BSA and height2.7.
Conclusions: LBM predictive equations are accurate in obese children. LBM is the strongest predictor of LV mass in obese children. LBMp is the most accurate anthropometric scaling variable for LV mass in LV hypertrophy detection. LBMp should be considered for widespread clinical use as the body size correcting variable for LV mass in obese children.
Author Disclosures: S.M. Chowdhury: None. M.H. Henshaw: None. J. Carter: None. T.N. Thomas: None. A.M. Atz: None.
- © 2015 by American Heart Association, Inc.