This year, the U.S. federal government will spend $21 billion for HIV/AIDS research, treatment, prevention, and related activities. Is this enormous expenditure paying off?

A study published in the July 1 issue of The Journal of Infectious Diseases indicates that it is - and more so than previously thought.

The study, by Rochelle P. Walensky, MD, MPH, Kenneth Freedberg , MD, MSc and colleagues at Massachusetts General Hospital and other centers appears at a time the world contemplates the 25-year anniversary of the first reported cases of AIDS and celebrates the 10-year anniversary of the use of multi-drug antiretroviral combinations for the treatment of HIV infections (also known as highly active antiretroviral therapy or HAART).

To analyze the impact of HAART on patient survival, the investigators used a computer simulation model to examine national surveillance and efficacy data for newly diagnosed adult AIDS patients under care in the United States from 1989 to 2003. They divided those years into “eras” corresponding to specific advances in AIDS care, and then used the simulation model to determine per-person survival time for each era, compared to the absence of treatment.

The results: Per-person survival increased by three months in 1989-92 and then by two years in 1993-95; both eras were characterized by the introduction of certain measures to prevent opportunistic infections. But in the four HAART eras spanning 1996 to 2003, per-person survival increased by approximately eight, 11, 12, and 13 years. Over the past 10 years, the investigators concluded, widespread adoption of HAART regimens, in addition to prophylaxis, led to at least 3 million years of life saved in the United States. Moreover, since approximately 25 percent of those infected with HIV in the United States are estimated to be unaware of their infection and little more than half of those who are aware of it are actually in care, Dr. Walensky and coworkers calculated that “an additional 740,000 years of life might have been saved had all AIDS patients in the U.S. received appropriate treatment upon diagnosis.”

In an accompanying editorial, Sten H. Vermund, MD, PhD, of Vanderbilt University observed that the benefits of HAART suggested by this study are greater than previously thought and may become still greater if certain barriers to care can be reduced or eliminated-such as the requirement for “extensive, expensive, time-consuming and intimidating” pre-test counseling for HIV infection. “If we address systematically the barriers to testing, care, and prevention,” he concluded, “then future modelers will describe the next 15-year period as having saved hundreds of millions of life-years, not just in North America but around the globe.”

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