How much fat loss is needed for lipoatrophy to become clinically evident?

The objective of this study was to evaluate how much limb fat is needed to be lost for lipoatrophy to become clinically evident. Antiretroviral drug-naive patients from a randomized trial comparing stavudine or abacavir plus lamivudine and efavirenz, who had subjective assessment to detect clinically evident lipoatrophy (standardized questionnaire) and objective measurements of limb fat (dual X-ray absorptiometry) at baseline, 48 weeks, and 96 weeks were included. ROC curves were used to assess the sensitivity and specificity of several cut-off values of absolute and percent limb fat loss for diagnosing lipoatrophy. Of 54 patients included, 13 (24%) had subjective lipoatrophy at 96 weeks. After 96 weeks, median limb fat change was -2.3 kg (interquartile range: -5.2, +0.2) and 0.4 kg (interquartile range: -7.2, +3.4) in patients with and without lipoatrophy, respectively. Median percent limb fat change was -45.5% (interquartile range: -78.0, +3.7) and 5.5% (interquartile range: -62.8, +95.6), respectively. The cut-off values of absolute and percent limb fat loss showing the best sensitivity and specificity values were -1.5 kg (sensitivity, 77%; specificity, 76%) and -30% (sensitivity, 85%; specificity, 73%). At least 30% limb fat is needed to be lost in HIV-infected patients for lipoatrophy to become clinically evident.