Fat distribution evaluated by computed tomography and metabolic abnormalities in patients undergoing antiretroviral therapy: preliminary results of the LIPOCO study

Fat distribution abnormalities have been reported in patients treated with various antiretroviral drug regimens. The LIPOCO study is an ongoing observational study of unselected HIV-infected patients which aims to better characterize such disorders and their metabolic correlations.

Cross-sectional analysis of data collected at baseline in the first 154 male patients included. Investigators divided patients into four predetermined clinical categories of fat distribution: lipoatrophy, obesity, mixed condition and normal. Body composition (tetrapolar bioelectrical impedance analysis and skinfold thickness), fat distribution [computed tomography (CT) scan], plasma glucose and insulin concentrations both fasting and during an oral glucose tolerance test and endocrine and lipid profile were measured and compared between the four groups.

Patients in the lipoatrophy group had significantly decreased abdominal and mid-thigh subcutaneous fat area values and elevated levels of plasma triglycerides. Patients in the obese and mixed groups had significantly increased intra-abdominal fat area values and elevated levels of plasma insulin and C-peptide. The CT scans identified some patients with isolated subcutaneous fat accumulation but no other alterations in fat distribution and no insulin resistance. Visceral adipose tissue measured by CT scan was positively correlated with fasting insulin and the sum of insulin levels (P < 0.0001). Fasting insulin as well as the sum of insulin levels were negatively correlated with the delta HIV-RNA (log(10)). In a multivariate logistic regression model, the use of stavudine significantly correlated with fat wasting in both nucleoside reverse transcriptase inhibitor and protease inhibitor groups: odds ratio (OR), 413 [95% confidence interval (CI), 5.2-999; P = 0.0068] and OR, 2.08 (95% CI, 0.92-7.0; P = 0.058) respectively, when compared with the use of zidovudine. Neither lamivudine or didanosine use, nor the use of protease inhibitors were significantly associated with fat distribution abnormalities or fat wasting.

These preliminary results suggest that three major types of fat distribution abnormalities may occur in isolation or in association in HIV-infected patients undergoing active antiretroviral therapy: a fat depletion or 'lipoatrophy' syndrome which might be related to the use of stavudine; a mixed or fat redistribution syndrome related to an unusual side-product of effective virus control; and a subcutaneous adiposity syndrome reflecting increase in caloric intake.