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CD4 Decline in Antiretroviral Naïve Adults in South Africa
Neil Martinson*1,2, M Ram3, G Gray2, G Barnes1, J McIntyre2, L Moulton3, and R Chaisson1
1Johns Hopkins Univ Ctr for Tuberculosis Res, Baltimore, MD, US; 2Perinatal HIV Res Unit, South Africa; and 3Johns Hopkins Univ, Bloomberg Sch of Publ Hlth, Baltimore, MD, US
Background: CD4 count is a proxy for the extent of immune
deficiency that occurs with HIV disease progression. Declines in CD4 count with time have been
described in cohort studies from developed countries. CD4 decline is an important component for
estimating demand for ARV services, estimating benefits of ARV treatment and
for individual level counseling on the rapidity of untreated disease
progression and prognosis. We report the
CD4 decline in a group of HIV-infected ambulatory, adults enrolled in a randomized
trial of preventive treatment for TB in South Africa where clade C
predominates.
Methods: HIV-infected, tuberculin skin test positive
adults enrolled in a trial of preventive treatment who were not eligible for
antiretroviral (ARV) treatment at the time of enrollment are included in this
analysis. Viral load (VL) and CD4 count
were assessed at enrollment and CD4 counts repeated annually. Individuals in follow up whose
CD4 counts decrease to less than 200 are referred for ARV
treatment and for the purposes of this analysis were censored in the interval
prior to taking ARVs. Any individual
with an increase in CD4 count of greater than 200 cells per annum was
excluded.
Results: Data for 821 subjects with multiple CD4 count
values (N=2111) were included in the analysis. The median age at enrollment was
30 years and the male to female ratio was 1:5. The total follow-up time was
1543 person years, with a median follow-up time per person of 1.91(Range 0.23
3.04) years. The mean baseline CD4 count was 547 cellsX106, and the overall
mean decline in CD count was 61cellsX106 per annum. Stratified by viral load at
baseline, the percent decline in CD4 count was 13.3% (95% CI 12.0%, 14.7%),
10.6% (95% CI 8.8%, 12.4%), and 13.8% (95% CI 12.1%, 15.5%) per annum for
baseline VLs of <10,000 (N= 314), 10,001-100.000 (N=338), >100,000
(N=122) copies/ml respectively. Similar declines were observed after adjusting
for age, gender, baseline hemoglobin, smoking status and drinking status
Conclusion: In this cohort of relatively healthy
HIV1-infected ARV naïve adults in a developing setting, CD4 decline is similar
to that observed in developed settings >3 years post seroconversion. Percent
declines in CD4 in this clinic population do not correlate with increasing viral
loads. These data suggest that time to antiretroviral eligibility (CD4<200)
from HIV seroconversion is in the order of 7-8 years.
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