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Clinical and Immunological Outcomes among Patients Older than 55 Years Receiving ART in South Africa
Mhairi Maskew*1,2, M Fox3,4, P MacPhail2, and I Sanne1,2
1Right to Care, Johannesburg, South Africa; 2Univ of the Witwatersrand, Johannesburg, South Africa; 3Ctr for Intl Hlth and Devt, Boston Univ, MA, US; and 4Hlth Economics Res Office, Johannesburg, South Africa
Background: Age is an important
risk factor for mortality for many diseases, but evidence is limited as to
whether initiating HIV treatment later in life increases the risk of early
mortality after initiating ART compared to those initiating ART earlier. Older
patients may have poorer immunological and virologic responses to ART.
Methods: This study was a retrospective cohort study
among 8713 HIV-infected adults initiated on ART at the Themba Lethu Clinic
between April 2004 to March 2008. We used proportional hazards and logistic
regression models to assess age-specific differences in early mortality, CD4
cell count response, failure to achieve virologic suppression, and risk of
viral rebound after suppression post ART initiation. Models were adjusted for
gender, baseline CD4 count, hemoglobin level, and body mass index.
Results: At baseline, patients aged 55 or older (n =
278, 3.2%) were similar to the 8435 (96.8%) patients under 55 in terms of
presenting CD4 count, hemoglobin level and body mass index. Older patients were
less likely to be receiving TB treatment (15.4% vs 6.5%, p <0.001)
and fewer presented with WHO clinical stage III or IV (44.9% vs 33.9%, p
= 0.002). The risk of death for older patients was twice that of younger
patients (HR 2.07, 95%CI 0.91 to 4.74) within 6 months of starting treatment
and also after 1 year on treatment (HR 2.01, 95%CI 1.02 to 3.96). Failure to
increase CD4 count by 50 cells/mm3 appeared more likely among older
subjects in the first 6 months after initiating treatment (OR 1.43,
95%CI 0.95 to 2.16) as well after one year on treatment (OR 1.74, 95%CI 0.92 to
3.28). There was no difference in odds of achieving
virologic suppression between age groups at 4 (OR 1.07, 95%CI 0.53 to 2.16) or 10
months (OR 1.04, 95%CI 0.47 to 2.31) post-ART initiation. We did not find
evidence of age group as a risk factor for rebound of HIV viral load after
achieving suppression (OR 1.19, 95%CI 0.27 to 5.16) in adjusted models.
Conclusions: The risk of early mortality after
initiation of ART among those aged 55 or older was double the risk of those
under 55. Decline in CD4 count numbers with advancing age may impair the
increase in CD4 cells after initiation of HAART in subjects over 55 years of
age. We found no evidence that failure to achieve viral suppression and viral
rebound were more likely in older age groups.
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