Lipid Metabolism in Treated HIV Infection

Patients infected with the human immunodeficiency virus (HIV) are prone to a great number of lipid and lipoprotein disturbances, as a result of both the infection itself and direct effects on lipid metabolism from the drugs used to treat HIV infection. These lipid disorders account for at least part of the increased risk of cardiovascular disease seen in this population. In general, evaluation and interventions for dyslipidemia in HIV-infected individuals should follow guidelines established for the general population. Special consideration, however, must be given to the potential for adverse drug interactions between lipid lowering drugs and the agents used to treat HIV infection. In this review, we summarize what is known about the relative tendency of different antiretroviral drugs to alter lipid levels, and suggest an approach to intervention for dyslipidemia in this population.

Introduction

Lipid disorders are highly prevalent among patients infected with the human immunodeficiency virus (HIV).1, 2, 3, 4, 5, 6 In addition to the dyslipidemias associated with untreated HIV infection, individuals treated with particular antiretroviral agents have an increased risk to develop, or have worsening of dyslipidemia.⁷ With modern combination antiretroviral therapy (ART)⁸, the long-term prognosis for HIV-infected persons has improved dramatically. With major reductions in the risk for opportunistic infections and improved survival, individuals with HIV infection will be at increased risk for many other major causes of age-related morbidity and mortality as experienced by the general population. This increased risk appears to be due to both HIV infection itself as well as treatment-related factors. As a result, interventions for lipid disorders and management of other cardiovascular risk factors have become increasingly important in the chronic care of these patients whose life expectancy can be expected to rival the general population.

Both ART 9, 10 and HIV infection itself ¹¹ are implicated in the increase in cardiovascular events among HIV-infected individuals. In part, this increase is attributable to treatment-induced lipid disorders.⁹ Clearly however, other mechanisms may also be involved.¹² In addition to dyslipidemia, other risk factors for coronary heart disease (CHD) are also more prevalent among HIV-infected patients than in the general population, including insulin resistance, diabetes mellitus, cigarette smoking, and endothelial dysfunction.¹³ Guidelines developed for the evaluation and treatment of lipid disorders in the general population 14, 15 are generally considered appropriate for use in HIV-infected individuals.¹ However, drug–drug interactions are a critical consideration whenever lipid lowering drugs are used in patients with HIV who are also receiving ART.