4th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 22-25 September 2002, San Diego, CA, USA

REPRODUCIBILITY OF DEXA ESTIMATIONS OF BODY FAT IN HIV LIPODYSTROPHY: IMPLICATIONS FOR RESEARCH

Antiviral Therapy 2002; 7:L48 (abstract 72)

RB Cavalcanti, A Cheung, J Raboud and S Walmsley
University of Toronto, Toronto, ON, Canada

OBJECTIVE: Dual-energy x-ray absorptiometry (DEXA) estimates of body fat composition are becoming increasingly common for the evaluation of HIV-lipodystrophy. However, no data is available on the reproducibility of DEXA body-fat measurements in this population. This information is essential if this tool is to be used as an endpoint in treatment trials. This study aimed at evaluating the reproducibility of DEXA body fat estimation in HIV positive subjects with and without lipodystrophy.

METHODS: Thirty patients, representing a spectrum of HIV lipodystrophy from none to severe, were evaluated with same-day repeat whole body DEXA scans. Scans were performed and analysed by the same technician using a Hologic QDR 4500A (Hologic, Waltham, Mass., USA) scanner. Root-mean-square coefficients of variation (RMS-CV) and standard deviations (RMS-SD) were calculated and used to estimate minimum detectable differences for body-fat content and body-fat percentage in different anatomical regions.

RESULTS: RMS-coefficients of variation were calculated for: arm-fat mass (3.97%), leg-fat mass (3.07%), trunk-fat mass (2.13%) and total-fat mass (1.55%). Minimal detectable differences at the 95% confidencelevel were derived for all measurements: arm-fat mass (11.01% or 159.8 g), leg-fat mass (8.51% or 312.7 g), trunk-fat mass (5.89% or 499.2 g) and total-fat mass (4.29% or 628.1 g).

CONCLUSIONS: DEXA measurements of regional body-fat mass in subjects with HIV lipodystrophy show similar reproducibility to that found in other populations studied. Minimal detectable differences were smaller than changes observed in published cohort data for all measurements except trunk-fat mass. DEXA is a sensitive tool for detecting long-term changes in peripheral fat among patients with HIV lipodystrophy.

Presenting author: RB Cavalcanti

2002-09-22
72

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