Immune recovery lags in older adults with HIV, Chinese study finds

While older adults starting HIV treatment achieved viral suppression at similar rates as younger people, their CD4 counts and CD4:CD8 ratio recovery lag behind, a Chinese single-center study showed.

About This Study

“Treatment outcomes among older HIV/AIDS patients receiving antiretroviral therapy: A nine year retrospective study” was published online on Jan. 10, 2024, in AIDS. The lead authors are Na Li and Hong-Yi Zheng, both of the Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences in Kunming, Yunnan, China.

Key Research Findings

This retrospective study investigated differences in HIV treatment response by age among 1,622 people (68% men) who started antiretroviral therapy at a single HIV clinic in China between 2010 and 2019. Participants were divided by age at baseline: younger (18-34 years old, 439 participants, 81% men), middle-aged (35-49 years old, 621 participants, 62% men) and older (≥ 50 years old, 562 participants, 66% men). Participants were followed for three to nine years.

Viral suppression rates (viral load ≤ 200 copies/mL) did not differ by age, with 95% of participants suppressed by the end of follow-up. Four years after starting treatment, CD4 counts among younger participants improved by 419 cells/µL, among middle-aged participants by 421 cells/µL, and among older participants by 323 cells/µL, relative to baseline. CD4:CD8 ratio recovery was slower among older participants (increasing from .30 at baseline to .58 after four years) compared to middle-aged participants (.31 at baseline; .67 at four years) and younger participants (.45 at baseline; .75 at four years).

Treatment-related adverse events and regimen changes were less common in younger participants than the other two groups. The study authors attributed the difference in part to the physiological impacts of aging (e.g., slower drug metabolization), as well as polypharmacy. Younger participants tended to switch antiretrovirals for personal reasons, such as pregnancy or financial constraints.

Discussion Highlights and Implications for Practice

Study limitations reported included its retrospective nature and single-center design, and a lack of data on medication adherence, comorbidities, polypharmacy, and other factors that could affect outcomes.

The researchers pointed out that injection drug use and hepatitis C coinfection were more common in the middle group, potentially explaining the lack of greater immune improvement in that age group. The poorer immune response among older participants may be related to declines in thymus and immune function as people age, they theorized.

Providers should consider age-related factors when prescribing treatment regimens, the authors said.

Further research into immune response when starting treatment at older ages that takes into account the data lacking in this study is also needed, they concluded.

By Barbara Jungwirth