Researchers say the proportion of HIV-positive patients in the United States whose infection with the AIDS virus are effectively controlled by drugs jumped from 45 to 72 percent during the past decade. But despite this impressive 60 percent gain in viral suppression rates, the new analysis falls short of previous estimates. The finding is important to HIV prevention campaigns because patients whose infections are suppressed by drugs are less likely to transmit HIV to others.

Over the past decade, new drugs and fixed-dose combination tablets have vastly improved HIV treatment. Early attempts to accurately gauge the impact of improved drug therapies often analyzed one-time blood tests, which indicated 77 to 87 percent of U.S. HIV patients getting drugs had eliminated the virus from their bloodstream. But these previous studies left lingering questions about the long-term effectiveness of antiretroviral drug treatments.

To gauge how well HIV drugs suppress the virus over time, researchers at Johns Hopkins University and the University of Pennsylvania reviewed a decade's worth of blood tests from more than 32,000 patients in 12 U.S. clinics. Compared to studies based on a single blood sample per patient, the new study found up to 10 percent fewer people for whom treatment lowered HIV-virus levels to an undetectable range.

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Rates of sustained virus suppression were especially low among younger patients, injection drug users, blacks, and those without private insurance. These discrepancies, say the authors, may be due to poor adherence to treatment, drug resistance, drug intolerance or toxicity. [END OPT]

“There is no denying the progress we have made over the past decade,” says author Baligh Yehia, “but more resources and new technology are needed to ensure that more patients have access to HIV therapy and obtain the full benefit of these drugs.”

This study appears in the current issue of the Journal of the American Medical Association.