Association of age at ART initiation with CD4:CD8 ratio recovery among virally suppressed people living with HIV, 2001–2019

Abstract

Objective: To investigate the association of age at anti-retroviral therapy (ART) initiation with CD4:CD8 T cell ratio in virally suppressed people with HIV on long-term ART, and to characterize potential CD4:CD8 ratio recovery in this population by age. Design: A longitudinal study of people attending an HIV clinic at the Royal Free Hospital NHS Trust, London, who initiated ART between 2001 and 2015, and achieved and maintained HIV-1 viral suppression (VL<100 c/mL). The association of age group at ART initiation with CD4:CD8 ratio at 5 and 10 years was assessed. Methods: Multivariable linear regression was used to investigate the relationship between age at ART initiation and log CD4:CD8 ratio, adjusting for demographic factors (gender/HIV transmission route, ethnicity), baseline CD4 count and calendar year. Results: The sample included 1859 people aged 20–78 (75% male, 56% white ethnicity). Overall, median CD4:CD8 T cell ratio increased from 0.24 at baseline to 0.77 at year 5 and 0.88 at year 10. Ratios increased among all age groups in unadjusted and adjusted models but increased less among older ages (baseline ages 60–69 and 70–79). Median ratios at year 5 were 0.85, 0.80, 0.72, 0.76, 0.6 and 0.44 respectively among people aged 20–29, 30–39, 40–49, 50–59, 60–69 and 70–79 years at baseline. Conclusions: In a virally suppressed London population, age had a substantial impact on CD4:CD8 ratio recovery, especially for those starting ART after age 60. Results may indicate the level of CD4:CD8 ratio recovery possible in an HIV positive, virally suppressed, aging population.