A large international study has provided evidence that people taking HIV treatment can now expect to live into their 60s and beyond. The study is published in the July 26th edition of The Lancet, and showed that an individual starting successful HIV treatment aged 20 would be expected to live to be 63, and that a patient initiating an anti-HIV drugs regimen aged 35 could live to the age of 67. It also provided evidence of the dramatic and continued decline in the risk of death amongst people with HIV since effective HIV treatment became available.
What is more, the researchers found that starting treatment with a CD4 cell count above 200 cells/mm3 would mean that a person aged 20 could expect to live to be 70, and that a 35 year-old could survive into their 72nd year.
Nevertheless, they still found that even in their most optimistic estimates, the life-expectancy of HIV-positive individuals was approximately ten years shorter than that of an HIV-negative individual. Furthermore injecting drug users and patients who started HIV treatment with lower CD4 cell counts had lower life-expectancies.
The author of an accompanying editorial calls these findings “exciting” and believes that they underline the importance of prompt diagnosis and treatment of HIV. He also suggests that the risk of death would be diminished and overall prognosis further improved by starting anti-HIV drugs with a CD4 cell count of 500 cells/mm3.
Almost immediately after multi-drug antiretroviral therapy became available in 1996, doctors observed dramatic reductions in rates of illness and death in HIV-positive patients treated with such drugs. A number of studies have shown that antiretroviral therapy has the potential to dramatically improve the prognosis of HIV-positive patients, but they have only considered patients in single cohorts or countries.
Therefore researchers from the Antiretroviral Cohort Collaboration which involves 14 large HIV cohort studies in Canada, Europe and the USA, looked at rates of mortality and the life-expectancy of over 43,000 patients who started HIV treatment for the first time between 1996 – 99, 2000 – 02 and 2002 – 05. They also looked at whether there were any patient characteristics which affected the risk of death or prognosis.
A total of 2056 (5%) patients died. The mortality rate fell from 16 deaths per 1000 person years between 1996- 99 to 10 per 1000 person years between 2002 – 05.
They also noted significant improvements in the prognosis for HIV-positive patients in the ten years of the study. Overall, a 20 year-old starting HIV treatment between 1996 and 2005 would be expected to live another 43 years. Between 1996 and 1999, they calculated that such a patient would live to be 56 years old, but in the period 2002 to 2005 this had improved to a little under 70 years.
There were also impressive improvements in the prognosis of 35 year-olds starting treatment, with an expectation of a further 32 years in life after HIV therapy was initiated. But, once more, prognosis improved over time from an expectation of a further 25 years of life in 1996 – 99, to 32 years by 2002- 05.
Patients who started HIV treatment with a low CD4 cell count (below 100 cells/mm3) had much higher mortality rates than patients initiating antiretroviral therapy with a CD4 cell count above 200 cells/mm3 (aged 20 – 44, 20 per 1000 person years vs. five per 1000 person years).
Furthermore a 20 year-old starting treatment with a CD4 cell count below 100 cells/mm3 would have a life-expectancy of 54 years compared to a life-expectancy of 70 years for a 20 year-old starting treatment with a CD4 cell count above 200 cells/mm3. The importance of CD4 cell count at the time of therapy initiation to prognosis was also seen in 35 year-olds, with patients with a CD4 cell count below 100 cells/mm3 expected to live until they were 62 compared to a prognosis of 72 years for patients with a CD4 cell count above 200 cells/mm3.
The investigators also found that women had a better prognosis than men, but that injecting drug users had a life-expectancy that was up to 20 years shorter than non-injecting drug users.
“There has been an improvement of outcomes with combination antiretroviral therapy between 1996 and 2005, characterised by a marked decrease in mortality rates” write the investigators. They attribute such reductions in mortality and improvements in life-expectancy to “improvements in therapy during the first decade of combination therapy.”
But they note that their study suggests that the prognosis of people taking antiretroviral therapy is still not normal. Picking up on this point, the author of the accompanying editorial highlights the findings of the SMART study which showed that patients with lower CD4 cell counts had a higher risk of serious non-HIV-related illnesses. The SMART study’s conclusions were one of the factors leading to HIV treatment guidelines recommending that antiretroviral therapy should be started at a CD4 cell count of 350 cells/mm3. The author notes the “clinical mischief of untreated HIV infection” and looks forward to the results of a clinical trial which could show if there is any benefit in starting HIV treatment at a CD4 cell count of 500 cells/mm3.
The Antiretroviral Cohort Collaboration. Life expectancy of individuals on combination therapy in high-income countries: a collaborative analysis of 14 cohort studies. The Lancet 372: 293 – 299, 2008.
Cooper DA. Life and death in the cART era. The Lancet 372: 266 – 267, 2008.