Diet, Exercise and/or Rosiglitazone for HIV-Associated Insulin Resistance

The purpose of this study is to determine if, in men and women with excess abdominal fat and insulin resistance, people with HIV infection respond differently than people without HIV to interventions that typically improve body fat distribution and insulin resistance. The specific interventions are:

1. Diet + exercise program.
2. Rosiglitazone treatment.
3. A combination treatment of diet + exercise program and rosiglitazone.

A constellation of nutritional alterations in HIV-infected patients receiving highly active antiretroviral therapies (HAART), including body fat redistribution with subcutaneous adipose tissue (SAT) wasting and visceral adipose tissue (VAT) accumulation, hyperlipidemia, and insulin resistance (IR) has been described. There is a major concern that these developments will be associated with adverse clinical outcomes related to atherosclerosis, as suggested by several case reports (Henry 1998, Behrens 1998, Gallet 1998, Vittecoq 1998). Although there are well documented associations among body fat distribution, insulin resistance, and adverse health outcomes, especially accelerated atherosclerosis, in non-HIV infected individuals, it is unclear if the relationships are affected by HIV infection, or if they reflect the same outcomes. This information is important, since understanding the interrelationships between body fat distribution and metabolism may guide the development of treatment strategies.

The specific hypotheses to be tested are:

1. HIV infection does not affect the relative reductions in visceral (VAT) and subcutaneous adipose tissue (SAT) resulting from diet + exercise, but decreases the effect of this therapy on insulin resistance.
2. HIV infection decreases the changes in insulin resistance and body composition (increase in SAT and decrease in VAT) expected with rosiglitazone.
3. The combination treatment of diet+exercise and rosiglitazone will reduce VAT to a greater extent than rosiglitazone alone, and will improve insulin resistance to greater extent than diet and exercise alone, however these effects will be blunted in HIV-infected subjects.