In people infected with human immunodeficiency virus (HIV), the virus that causes AIDS, high-risk behavior, HIV infection itself, as well as late initiation and early discontinuation of anti-HIV therapy all contribute to substantial decreases in life expectancy, United States researchers report.

Using a comprehensive computer model of HIV disease, the researchers simulated cohorts of HIV-infected individuals and compared them with uninfected individuals who had similar demographic characteristics.

"We estimated that for people in the United States living without HIV, life expectancy beginning at age 33 is an additional 43 years," first author Dr. Elena Losina, of Massachusetts General Hospital, Boston, told Reuters Health.

"High risk behavior, such as substance abuse, on average, accounts for an 8 year reduction in life expectancy," Losina added.

HIV infection itself reduces life expectancy by an additional 12 years and a late start or premature discontinuation of HIV treatment further reduces life expectancy to a total of 23 years, she and colleagues report in the journal Clinical Infectious Diseases.

"The current therapy for HIV is very effective," Losina commented, "but unless HIV-infected patients initiate treatment on time and stay on treatment, the treatment benefits would be truncated substantially."

Minorities, especially minority women, tend to initiate therapy later and are more likely to drop off from care, and this "leads to disproportional losses in life expectancy in these population groups," she said.

"There is a critical need for people with HIV to begin care in a timely way and to remain in care," senior investigator Dr. Kenneth A. Freedberg, also from the Massachusetts General Hospital, said in a statement. "HIV testing for all adults in the United States, as currently recommended, with effective linkage to care, will have important survival benefits."