Treatment with protease inhibitors is associated with peripheral insulin resistance, leading to impaired or diabetic oral glucose tolerance in some of the patients, and with hyperlipidaemia. Overall, there is a large variation in the severity and clinical presentation of protease inhibitor-associated metabolic side-effects.

These data indicate that increased triglycerides in HIV-infected patients with ART are primary due to reduced rates of VLDL transfer into denser lipoproteins implying a lower rate of lipoprotein lipase-mediated delipidation. In addition, total apo B synthesis was increased and shifted toward triglyceride-rich VLDL1. Overall, this lipoprotein profile in patients with ART-associated dyslipidemia implies an increased risk for cardiovascular events.

The pathogenesis of some components of the lipodystrophy (LD) syndrome might be linked to the use of nucleosides. Earlier reports did not compare treatment regimens according to the nucleoside backbone. We studied a cohort of individuals who did not switch between stavudine and zidovudine. LD was defined to be present if one of three criteria was met: self-report by the patient, observation by an investigator who had known the patient since commencement of highly active antiretroviral therapy (HAART), or examination by a physician masked to therapy. The mean duration of therapy was 101 weeks (range: 26-234 weeks). Overall prevalence of LD was 48.7%. Lipoatrophy and lipohypertrophy occurred in 33.9% and 28.7% of patients, respectively. Logistic regression showed four parameters to be significantly associated with lipoatrophy: HAART longer than 2 years (p =.002, odds ratio [OR] = 4.4, 95% confidence interval [CI]: 1.608-11.965), baseline viral load >100,000 copies/ml (p =.004, OR = 4.3, CI: 1.726-11.197), age >40 years (p =.016, OR = 3.2, CI: 1.247-8.373), and white ethnicity (p =.041, OR = 5.4, CI: 1.070-28.184). Cholesterol levels of >200 mg/dl at baseline were associated with a risk reduction (p =.047, OR = 0.36, CI: 0.130-0.987). Use of lipohypertrophy as a dependent variable resulted in a significant association with HAART duration (p = 0.028, OR = 2.7, CI: 1.2-6.5) and protease inhibitor use (p =.014, OR = 3.8, CI: 1.3-11.2). LD prevalence is similar with both backbones using stavudine or zidovudine. This is the first time that baseline cholesterol was shown to be significantly associated with lipoatrophy.

Antiretroviral therapy (ART) is frequently associated with metabolic alterations, including insulin resistance and diabetes mellitus. In this pilot study, we evaluated the effect of the PPARgamma activator troglitazone on ART-associated insulin resistance in HIV-infected patients with ART-associated diabetes mellitus. Six patients with protease inhibitor (PI)-associated diabetes mellitus, lipodystrophy and dyslipidemia were treated with troglitazone 400 mg q.d. for 3 months. Previous oral antidiabetics were discontinued prior to the study. At baseline and after 3 months, insulin sensitivity (intravenous insulin tolerance test), body composition (multifrequence bioelectrical impedance analysis) and fat distribution (CT scan quantification) were assessed. Glycaemic control (fasting and postprandial blood glucose, fructosamine, glycosylated haemoglobin) and serum lipid status were determined monthly. In four of the six patients, there was a clear improvement in insulin sensitivity, resulting in a reversal of insulin resistance in two of these patients. Overall, there was an increase in lean body mass and a decrease in total body fat. The volume of visceral adipose tissue decreased whilst the volume of subcutaneous adipose tissue increased. Total cholesterol, LDL and HDL cholesterol increased, and total triglycerides and VLDL-cholesterol decreased. No adverse effects such as hepatotoxicity were observed. Treatment with troglitazone 400 mg q.d. can ameliorate and in some cases even reverse ART-associated insulin resistance. Therefore, further studies including non-diabetic patients with ART-associated insulin resistance may be helpful in evaluating the long-term effects of thiazolidinediones on ART-associated insulin resistance and other metabolic complications, such as adipose maldistribution and dyslipidaemia.

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