HIV patients can expect to live 13 years longer because of advances in antiretroviral therapy, according to researchers.

The therapy has slashed deaths by 40 per cent among 43,355 HIV patient-participants in Europe and North America, bolstering the call for improved anti-HIV efforts worldwide, the study authors said.

The authors looked at changes in life expectancy and mortality among the 43,355 patients taking combination antiretroviral therapy (cART). Data was based on 14 studies in Europe and North America.

"Since their introduction in 1996 cART regimens have become more effective, better tolerated and easier to follow," said Michael Mugavero, assistant professor in University of Alabama Division of Infectious Diseases and a co-author of the study.

"We are now seeing the benefits of years of research, hard work and efforts to make these medications widely available. This has led to dramatic improvements in life expectancy, but patients who start cART with more advanced HIV infection do not have the same level of benefit," Mugavero said.

The new study found cART yielded a 13.8-year life-expectancy increase - from 36.1 years in study participants who began therapy during the 1996-1999 period to 49.9 years in participants who began therapy during the 2003-2005 period.

Despite the good results, the study found life expectancy for HIV patients is far lower on average than the general population, which includes all those with other chronic illnesses.

The study was published in the British medical journal The Lancet.