The study, by Rochelle P. Walensky, MD, MPH, Kenneth Freedberg , MD, MSc and colleagues at Massachusetts General Hospital and other centres 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 analyse 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 characterised 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, eleven, twelve, and 13 years.

Over the past ten years, the investigators concluded, widespread adoption of HAART regimens, in addition to prophylaxis, led to at least three 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, Walensky and co-workers 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."; Source: Infectious Diseases Society of America