The United Nations' estimates from 2007 indicate that worldwide about 33 million people are currently living with HIV; of these, 8% became HIV infected within that year whereas 6% succumbed to AIDS. In the United States and Western and Central Europe, 2.1 million people are living with HIV, a number that continues to rise mainly due to access to modern antiretroviral therapy. In contrast to global figures, in this region, 4% acquired HIV in the past year and 1.5% died of AIDS.1 Consequently, in the United States and Europe, and hopefully soon in a significant portion of the developing world, HIV-infected individuals are growing older and are at risk for developing the same lifestyle-related conditions as their noninfected counterparts. As a result, physicians treating HIV-infected patients must now consider comorbid conditions such as the metabolic syndrome, type 2 diabetes, and cardiovascular disease when optimizing therapeutic strategies for an individual. This is in addition to the already increased risk for these conditions posed by the HIV virus itself and the potential lipodystrophy linked to components of highly active antiretroviral treatment (HAART). Features of HIV-associated dyslipidemia are similar to those found in the metabolic syndrome, raising the concern that risk of cardiovascular disease is also elevated among HIV-infected patients.
Recognized soon after the advent of HAART, various antiretroviral components have been associated with the metabolic disturbances and body shape changes experienced by many patients receiving lifesaving antiretroviral treatment. Protease inhibitors and, later, nucleoside reverse transcriptase inhibitors were found to contribute to lipid-related abnormalities. Further details emerged that showed a differential risk for lipid-related liabilities among individual drugs within each class. This spurred the development of new members of these drug classes with better lipid profiles and the search for other antiretroviral classes that spare these effects. Another line of research is aimed at minimizing exposure to the specific medications most known to contribute to metabolic abnormalities by the redesign of HAART regimens.
The manuscripts in this supplement will review the evidence detailing the contribution to dyslipidemia and lipodystrophy from HIV itself, from antiretroviral therapy, and from environmental factors that the entire population is exposed to as it ages.
Dr. Kotler will discuss the interrelationships between HIV/AIDS, serum lipid concentrations, and cardiovascular disease, including the association between dyslipidemia and cardiovascular disease, the effects of HIV infection on serum lipid concentrations, the effects of antiretrovirals on serum lipid concentrations, the association between HIV infection and cardiovascular disease, and the management of cardiovascular disease risk associated with dyslipidemia.
Dr. Tebas will describe the metabolic syndrome and the associated increase in risk for development of cardiovascular disease and type 2 diabetes. The high insulin levels and insulin resistance frequently seen in HIV-positive individuals are also associated with an increased risk of cardiovascular events that are independent of lipoprotein levels.
Dr. Wohl will review the morphological changes that are associated with fat redistribution attributed to HIV therapy. Lipoatrophy is characterized by selective loss of subcutaneous adipose tissue, most commonly of the limbs, face, and abdomen, whereas lipohypertrophy presents as accumulation of visceral fat of the abdomen, back of the neck, and breasts. The association between each type of adipose-related shape change and specific antiviral medications will be detailed, as will the proposed etiologies of these changes and evidence-based approaches to their management.
Knowledge of the metabolic consequences of both retroviral infection and treatment is crucial to the successful long-term management of HIV. This educational activity is intended to review the metabolic aspects of treating HIV that are not typically the focus of infectious diseases specialists but can have major implications for improving the quality of life of HIV-infected individuals and maintaining adherence to HAART treatment regimens.