December 30, 2009

Cardiovascular Disease More Likely in People With Kidney Dysfunction

People with reduced kidney function are more likely to also have cardiovascular disease—which can include heart attacks and strokes—according to a study published online December 17 in AIDS.

Though potent combination antiretroviral (ARV) therapy has cut rates of illness and death dramatically since its introduction in the late 1990s, certain diseases remain more common in people with HIV than in their HIV-negative counterparts. Two of these are kidney disease and cardiovascular disease. Thus far, however, research regarding a possible link between the two diseases in people with HIV has been limited.

To explore this connection, Elizabeth George, MBBS, from the All India Institute of Medical Sciences in New Delhi, and her colleagues examined data from the Johns Hopkins Clinical Cohort, which includes 6,000 HIV-positive patients seen at the Johns Hopkins medical clinics in Baltimore. Between 1998 and 2008, 63 people in the cohort had a verifiable cardiovascular event, such as a heart attack or stroke. These individuals were compared with 252 people who did not have an event but who resembled the people who did in most characteristics.

The average age of both groups was 49, roughly half were male, and about 84 percent were black. People who’d sustained a cardiovascular event tended to have lower CD4 counts and slightly higher rates of risk factors such as obesity, smoking and high blood pressure than people who hadn’t had an event. Use of ARV therapy was similar between the two groups. Kidney function was assessed in both groups by measuring the glomerular filtration rate (GFR), the presence of serum proteins in the urine (proteinuria) and other measures. A reduced GFR or the presence of proteinuria indicates reduced kidney function.

When George’s team ruled out contributing factors—such as diabetes, high blood pressure, a previous cardiac event and cholesterol levels—reduced kidney function significantly predicted a cardiovascular event. People with a GFR of between 60 to 89 milliliters per minute (ml/min) were 80 percent more likely than people with a GFR of more than 90 ml/min to have had a cardiovascular event. People with a GFR less than 60 ml/min were more than six times as likely to have had a cardiovascular event. People with proteinuria were also significantly more likely to have had a cardiovascular event, and proteinuria combined with GFR further increased the risk.

The authors conclude: “Our findings require further confirmation, but suggest the potential value of early screening and treatment of [kidney disease] in HIV-1 infected patients, particularly those with other cardiovascular risk factors.”

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