The Effect of Anti-HIV Therapy on Fat Metabolism in HIV-Positive Patients

The purpose of this study is to see how taking certain anti-HIV drugs affects the way the body metabolizes fat. This study will evaluate patients who are enrolled in CPCRA 058 (the FIRST [Flexible Initial Retrovirus Suppressive Therapies] study) by looking for changes in cholesterol levels, levels of fat in the blood, and body fat distribution. Patients in the FIRST study receive an anti-HIV drug regimen which contains a protease inhibitor (PI), a nonnucleoside reverse transcriptase inhibitor (NNRTI), or both.

Anti-HIV drug therapy using PIs has become very common treatment for HIV-positive patients. Recently, however, serious side effects involving how the body uses fat are being reported in patients taking PIs. Examples of these side effects are a redistribution of body fat, high cholesterol level, and development of diabetes. However, some of these side effects have also been seen in patients who are not taking PIs. It is important to determine whether or not these side effects are directly related to PI use. In this study, patients on different drug combinations, either with or without a PI, will be compared.

Close to 3 years into widespread PI use, several toxicities, including metabolic alterations, are being reported increasingly in conjunction with the use of PI-containing regimens. Some of the manifestations of these metabolic alterations include hyper/dyslipidemia, hyperglycemia, insulin resistance and glucose intolerance, lipodystrophy (in face and extremities), and body fat redistribution (e.g., central obesity and buffalo humps). Despite reports of increasing prevalence of metabolic complications among PI users, the question of whether they result from PI therapy has not been answered. Some of these complications, e.g., a decrease in peripheral fat with an increase in visceral fat and buffalo hump, have been observed in HIV-infected individuals who were not receiving PIs. This study compares 3 different antiretroviral regimens used in the FIRST study (CPCRA 058), 1 of which does not contain a PI, and examines metabolic alterations which occur.

This study enrolls patients simultaneously co-enrolling in the FIRST protocol; 120 patients from each of the FIRST study strategy groups. At entry, Months 1 and 4, and then every 4 months, blood is drawn to measure serum glucose, insulin, total cholesterol, HDL cholesterol, LDL cholesterol, and triglyceride levels. At entry and Months 4, 8, 12, and then every 12 months, body cell mass, and body fat by bioelectrical impedance analysis (BIA) are assessed. [AS PER AMENDMENT 7/5/01: At Months 4, 8, and 12, then every 4 months through closure of the FIRST protocol] patients are weighed and skinfold measurements and body circumference measurements are done. The skinfold and body circumference measurements will be discontinued after the study has collected a minimum of 2 years of follow-up data on all participants. Statistical evaluations are performed on the data.