First the good news: People with HIV may enjoy life spans close to normal if they are on antiretroviral therapy, maintain low viral loads and CD4 counts above 350, are not coinfected with viral hepatitis, and are not injection drug users, according to a new study from the United Kingdom, aidsmap reports. Furthermore, those who survive past 60 may have life expectancies that surpass normal, thanks to the better overall health care monitoring they experience compared with the general population. Now the not-so-good news: An Australian study questions how solid such projections may be in the face of successive therapies failing over time, even in resource-rich countries. Both studies were presented at the 11th annual International Congress on Drug Therapy in HIV Infection in Glasgow.

The projections on life expectancy derive from the U.K. Collaborative HIV Cohort (UK CHIC) study, which is a database of 43,000 patient records collected from 20 of the United Kingdom's largest HIV clinics. UK CHIC's Margaret May, PhD, examined mortality data concerning people who began taking antiretrovirals (ARVs) after age 20 between 2000 and 2008, and she tracked them until 2010. As data points, the study took each patient's CD4 count and viral load just before starting therapy and compared them with the last CD4 and viral load figures for each subsequent year. Final results were expressed as the number of subsequent years a patient could expect to live past his or her 35th birthday. The study excluded injection drug users.

In general, maintaining a higher CD4 count promised significant extra years of life. Five years into ARV treatment, 35-year-old male patients with counts between 350 and 500 could expect to live to 77—and to 81 if their CD4 counts were higher than 500. On the flip side, those who fail to develop a suppressed viral load would lose 11 years of life expectancy. And people whose CD4 counts remain below 200 after five years on ARVs could expect to live only to 55 on average.

Meanwhile, scientists at the University of New South Wales in Australia projected that, if current trends of treatment failure continue, people on ARVs may run out of effective therapies after an average of 43 years, with 10 percent of people running through the available options after about 23 years.

To read the aidsmap report, click here.

To read the British study abstract, click here.

To read the Australian abstract, click here.