WHO recommends initiating combination antiretroviral treatment (ART) at the minimal threshold of 350 CD4 cells/mm3. In sub-Saharan Africa, the time for a recently infected patient to reach this threshold is unclear.
We estimated the probability of reaching different CD4 thresholds over time in the ANRS 1220 cohort of HIV-1 seroconverters in Côte d’Ivoire. CD4 slopes were estimated using a mixed linear model. Probabilities of crossing the 350 and 500 CD4 cells/mm3 thresholds were estimated by the Kaplan-Meier method.
Between 1997 and 2009, 304 recent seroconverters have been enrolled in the Primo-CI cohort (62% men, median baseline age 29 years, median time since the estimated date of seroconversion 9 months). The probability of having a first CD4 count below 500/mm3 was 0.57, 0.72, 0.79 and 0.84 at study entry, 2, 4 and 6 years, respectively. For a first CD4 count below 350/mm3, these figures were 0.29, 0.40, 0.55 and 0.67. The time for 75% of patients to reach the threshold was 3.0 years for 500 CD4/mm3 and 7.0 years for 350 CD4/mm3.
Almost one third of recent seroconverters had a CD4 count below the current ART eligibility threshold at first contact, about 6% more crossed it each subsequent year, and 25% remained above this threshold after 7 years. If the threshold was raised to 500 cells/mm3, 57% of recent seroconverters would immediately be eligible, while 14% would remain above the threshold at 7 years. These results should help modelers and treatment providers anticipate the need in antiretroviral drugs.