Prevalence of Metabolic Syndrome Among HIV Patients

Recently published observations (1) suggest that among HIV-positive patients treated with highly active antiretroviral therapy (HAART), the incidence of cardiovascular diseases is increased. Until now, no specific risk factors have been identified except for those related to behavior or metabolic abnormalities. So far, a sum of metabolic abnormalities have frequently been reported among these patients, including increased lipid levels, abnormal fat distribution, elevated blood pressure, and disturbance in glucose metabolism (2). Studies designed to identify subclinical atherosclerosis in HIV-infected patients on HAART have been inconclusive. Numerous modalities, including carotid intimal thickness measurement, brachial reactivity, and electron beam computed tomography, have shown varying results; at this time, it is unclear what the results mean. The metabolic syndrome is a cluster of risk factors (disturbance in glucose metabolism, central obesity, hypertension, and dyslipidemia) caused by insulin resistance (3,4). Metabolic syndrome is considered a powerful independent risk factor for cardiovascular morbidity and mortality (4). Insulin resistance is frequent among HIV patients on HAART (5), but there are no data about the prevalence of the metabolic syndrome in these patients.

We evaluated the prevalence of the metabolic syndrome in a large cohort of HIV patients on HAART. We studied 553 patients (321 men, 232 women) with a mean age of 37.1 ± 7.3 years (range 20–61). Metabolic syndrome has been defined according to criteria released by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults III (3). In particular, HIV patients with three or more of the following risk factors were defined as having the metabolic syndrome: 1) high fasting glucose (≥6.1 mmol/l), 2) central obesity (waist circumference >102 cm in men and >88 cm in women), 3) hypertension (≥130/85 mmHg), 4) hypertriglyceridemia (≥1.69 mmol/l), and 5) low HDL (<1.04 mmol/l in men and <1.29 mmol/l in women) (3).

Among HIV patients, 133 (24.0%) showed high fasting glucose or antidiabetes medication use, 209 (37.8%) had central obesity, 234 (42.3%) showed hypertension, 328 (59.3%) showed hypertriglyceridemia, and 290 (52.4%) showed low HDL. One single risk factor was present in 108 (19.5%) patients, two in 95 (17.2%), three in 146 (26.4%), four in 67 (12.1%), and five in 38 (6.9%). Of the subjects, 99 (17.9%) showed no risk factors. We found that 251 patients had the metabolic syndrome (at least three risk factors), leading to a prevalence of 45.4%. This prevalence was more than twofold that reported recently by Ford et al. (6) in the general population and was even higher than that observed in subjects older than 60 years (6). Although we are referring to two different populations (Italian HIV patients and American adults), the difference in the prevalence of metabolic syndrome between a cohort of HIV patients on HAART and the general population appears to be very remarkable.

Our data show that among HIV patients, the prevalence of metabolic syndrome is impressively high, considering the mean age of our sample population; this finding could explain why HIV patients may have an increased risk for cardiovascular disease. Despite the improvement of prognosis related to HIV infection due to the effect of antiretroviral therapy, an increase of cardiovascular morbidity and mortality should be expected. In the years to come, cardiovascular diseases may become important clinical problems for HIV-infected patients, mainly because the cluster of risk factors defining the metabolic syndrome increases cardiovascular risk more than each single component (4). On this basis, a close monitoring of cardiovascular risk factors and their aggressive treatment in HIV patients to reduce cardiovascular-related morbidity and mortality appear necessary.