ART increases life expectancy by 30 to 40 years: impact of CD4 count, sex and calendar year
1 June 2023. Related: Antiretrovirals, Treatment strategies, Ageing and life expectancy.
Kirk Taylor, HIV i-Base
The Lancet HIV has published a large collaborative cohort study (n=206,981) that predicts life expectancy for people living with HIV on long-term ART. [1]
Two cohorts included data from people who started ART between 1996 and 2019 and who had been on ART for ≥1 year. Life expectancy was estimated from associations between mortality and clinical and demographic factors.
This was a retrospective analysis of the Antiretroviral Therapy Cohort Collaboration and the UK Collaborative HIV Cohort Study. Mortality risk ratios were calculated by Poisson regression models for women and men, based on starting ART before or after 2015, and reported as predicted life years remaining at age 40.
When ART was started before 2015, estimated life expectancy was 75.8 years (95% CI: 75.2 to 76.4 years) for women and 74.5 years (95% CI: 73.8 to 75.2 years) for men. Life expectancy increased for people who started ART after 2015 and is estimated at 79 years (95% CI: 78.5 to 79.5 years) for women and 77.0 years (95% CI: 76.5 to 77.6 years) for men. Life expectancy estimates correlated with CD4 count at start of follow-up. Table 1 summarises estimated life expectancy by sex, CD4 count and year of ART initiation.
These data suggest that life expectancy has increased by 4.6 years for women and 1.8 years for men relative to predictions made in 2016 by the Kaiser Permanente analyses. [2]
Overall, life expectancy remains lower than for HIV negative individuals.
The largest influence on life expectancy was CD4 count at start of follow-up. These data highlight the efficacy of ART and the importance of early diagnosis and sustained ART. Starting ART after 2015 increased life expectancy by about three years.
Table 1: Predicted life expectancy in years (95% CI) stratified by sex, year of ART initiation and CD4 count at start of follow-up.
| Women | Men | |||
| Baseline CD4 (cells/mm3) | 1996 to 2014 | 2015 to 2019 | 1996 to 2014 | 2015 to 2019 |
| 0 to 49 | 69.4
(58.2 to 60.5) |
64.9
(63.9 to 65.9) |
58.2
(57.1 to 59.4) |
63.7
(62.7 to 64.8) |
| 50 to 99 | 63.2
(62.2 to 64.3) |
68.9
(67.9 to 69.8) |
61.3
(60.2 to 62.4) |
66.9
(65.9 to 67.9) |
| 100 to 199 | 67.8
(66.8 to 68.7) |
73.0
(72.2 to 73.7) |
66.2
(65.2 to 67.2) |
71.7
(70.9 to 72.5) |
| 200 to 349 | 73.6
(72.8 to 74.3) |
78.0
(77.4 to 78.5) |
72.1
(71.3 to 72.9) |
76.5
(75.9 to 77.1) |
| 350 to 499 | 77.6
(77 to 78.1) |
80.8
(80.4 to 81.2) |
76.2
(75.6 to 76.9) |
78.4
(77.9 to 78.9) |
| ≥500 CD4 | 80.2
(79.7 to 80.6) |
82.0
(81.7 to 82.3 |
78.0
(77.5 to 78.5) |
79.2
(78.7 to 79.7) |
comment
These results are encouraging and are welcomed. They provide confidence for people to make long-term life plans and they challenge the continued stigma associated with HIV.
However, there are also significant differences within the average estimates.
An editorial comment on this study noted that life expectancy still remains lower than the general population. Also, that comorbidities occur approximately ten years earlier for people living with HIV and that this would likely impact on differences in quality of life. [3]
Although there were few differences in life expectancy between women and men in this study, in relative terms this shows a reduced benefit for women, who generally live an additional 4 to 8 years compared to men. No data was presented for transgender individuals.
Injecting drug use was also linked to shorter life expectancy.
The US cohort also reported that life expectancy was approximately a decade shorter for Black compared to white gay and bisexual men and a similar impact from injecting drug use.
References
- Trickey A et al. Life expectancy after 2015 of adults with HIV on long-term antiretroviral therapy in Europe and North America: a collaborative analysis of cohort studies. Lancet HIV, 10(5): E292-307. (20 March 2023).
DOI: 10.1016/S2352-3018(23)00028-0
- Marcus JL et al. Narrowing the gap in life expectancy between HIV-positive and HIV-negative individuals with access to care. J. AIDS, 73(1): 39-46. (01 September 2016).
DOI: 10.1097/QAI.0000000000001014 - Klein MB. Living longer with HIV: gains for some but not for all. Lancet HIV. 2023 May;10(5):e275-e276.
DOI: 10.1016/S2352-3018(23)00060-7.