Incidence of and risk factors for insulin resistance in treatment-naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy

Objectives: to assess the incidence and risk factors for insulin resistance (IR) in a cohort of naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy (HAART). Design: prospective, two centre, observational, cohort study. Methods: One-hundred and thirty-seven patients who started HAART and maintained the same regimen for 48 weeks were included. IR was determined by the homeostasis model assessment (HOMA-IR) method. Individuals with a HOMA-IR value > 3.8 were defined as insulin resistant. Independent associations with the development of IR at 48 weeks were evaluated. Results: Seventeen (12.4%) individuals showed a HOMA-IR value > 3.8 at baseline and were excluded for incidence analyses. Fifteen patients developed IR at 48 weeks of HAART, giving an incidence of 13%. Independent predictors of the development or IR were indinavir exposure (P-coefficient 5.45, 95% confidence interval [CI] 1.30-22.8; P=0.02), and hepatitis C virus (HCV) antibody positivity (beta-coefficient 5.22, 95% CI 1.34-20.33; P=0.011). The appearance of IR was associated with a higher BMI (beta-coefficient 1.72 for each 2 kg/m(2) increase, 95% Cl 1.54-1.94; P=0.02) and with the presence of lipodystrophy at 48 weeks (P-coefficient 5.59, 95% Cl 1.45-21.5; P=0.01). Conclusions: HAART induces the development of IR in previously naive non-insulin-resistant HIV-infected individuals, with an incidence of 13% in the first year of therapy. Indinavir exposure, and HCV coinfection are associated with an increased risk of developing IR.