Anthropometry in the assessment of HIV-related lipodystrophy

Infection with HIV causes a spectrum of clinical problems. Abnormalities in body composition have been reported in 40-50% of ambulatory HIV-infected patients. Progressive, involuntary weight loss is an AIDS-related metabolic disorder called "wasting syndrome". Its etiology in untreated HIV infection, is multifactorial. This condition is still common in developing countries while is much more rarely seen in industrialized countries. Indeed, in the late 1990s, reports of unusual changes in body fat distribution named "Lipodystrophy" began to appear in HIV patients. This syndrome includes peripheral fat loss (lipoatrophy; LA), central fat accumulation (lipohypertrophy; LH) separately present or in combination in the same individual (mixed forms). In this clinical condition, abnormal fat accumulation is observed in intraabdominal region, as well as in subcutaneous area of the cervical, retroauricolar, dorsal and pubic region. Abnormal fat loss is observed from the arms and legs, face, and buttocks. The driving force behind lipoatrophy is undoubtedly the cumulative exposure to thymidine analogue (TA) drugs. Risk factors for fat accumulation, on the contrary, are still obscure. The absence of a clear-cut definition unavoidably has led to uncertainty about changes in prevalence and incidence of lipodystrophy over time. The absence of a precise definition of lipodystrophy suggested the need for regulatory consideration for its anthropometric measurement and the choice of objective treatment goals. Objective lipodystrophy (LD) measurement tools analysed refer to general anthropometry evaluation (BMI, Waist girth and waist to hip ratio), as well as to radiological evaluation for lipoatrophy or fat accumulation (Ultrasound, Dual Energy X-ray absorptiometry, abdomen and limb Computed Tomography or Magnetic Resonance). Given that lipoatrophy and fat accumulation may coexist in the same individual, radiological tools for measuring both these changes are needed for the assessment of the same individual analysing at the same time the degree of lipoatrophy in the limbs and fat accumulation in the visceral area: lipoatrophy is measured with Dual Energy X-ray absorptiometry (DXA); fat accumulation is usually measured with lumbar computed tomography (CT) or with Magnetic resonance Imaging (MRI). Several studies have investigated changes in body composition that occur in HIV-infected individuals.