Differentiating hyperlipidaemia associated with antiretroviral therapy

Abstract

Background: Hyperlipidaemia associated with antiretroviral treatment has led to concerns for an increased cardiovascular risk in HIV-infected patients. Objective: To assess this cardiovascular risk by comparing the lipoprotein pattern of antiretroviral-treated and untreated HIV-positive patients with patients with familial combined hyperlipidaemia (high cardiovascular risk) or familial hypertriglyceridaemia (low cardiovascular risk). Methods: Fasting serum samples were drawn from consecutive patients with HIV infection or lipoprotein disorders. Total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1 and B were determined in serum. Very low density lipoprotein (VLDL) was prepared by ultracentrifugation and analysed for cholesterol, triglycerides and apolipoprotein B. Results: Lipoprotein disorders were found in 114/187 HIV-positive patients (61%). Of these, according to the Fredrickson classification, 10% were type IIa (elevated LDL-cholesterol), 14% type IIb (elevated LDL- and VLDL-cholesterol) and 76% were type IV (elevated VLDL-cholesterol). VLDL composition was analysed in 34 HIV-positive patients with type IV hyperlipidaemia. The ratio of VLDL-triglycerides to VLDL-apolipoprotein B in these patients was 16.2 ± 6.0. This ratio was not different from 14 patients with famlial hypertriglyceridaemia (16.9 ± 6.0; P = 0.61), but differed substantially from 10 patients with familial combined hyperlipidaemia (6.8 ± 1.0; P < 0.0001). Conclusions: In HIV-infected patients with high VLDL, large VLDL particles were found with no increase in number. This pattern resembles familial hypertriglyceridaemia . It is different from familial combined hyperlipidaemia, where an increase in number of small-sized VLDL particles occurs. Further research is needed to assess the contribution of VLDL-associated hypercholesterolaemia in those taking antiretroviral drugs to the cardiovascular risk profile of HIV-positive patients.