Failure to achieve a CD4+ cell count response on combination antiretroviral therapy despite consistent viral load suppression

Abstract

To assess CD4 cell count recovery in people severely immunosuppressed at start of antiretroviral therapy (ART) who achieve and maintain viral load suppression. Eligible participants from the UK Collaborative HIV Cohort Study started ART with at least three drugs after 1 January 2000. Participants were required to have pre-ART CD4 cell count below 100 cells/μl, at least 2 years of follow-up on ART, have achieved viral load suppression (≤ 50 copies/ml) by 9 months after starting ART and to have maintained this throughout follow-up. Participants were further required to be regularly engaged with care. We calculated the proportion of people who failed to achieve a CD4 cell count of more than 100, 150, 200, 350 and 500 cells/μl by the time of the last follow-up, or 5 years from start of ART, whichever occurred first (censoring date). Of the 400 participants [median (interquartile range) pre-ART CD4 cell count of 38 (14-65) cells/μl], 2 (0.5%), 8 (2%), 28 (7%), 131 (33%) and 259 (65%) failed to achieve a CD4 cell count of more than 100, 150, 200, 350 and 500 cells/μl, by the censoring date, respectively. Kaplan-Meier estimates of the proportion of people reaching each CD4 cell count threshold after 1 year on ART were 88, 70, 50, 14 and 3%, respectively, and after 3 years on ART, 98, 95, 90, 59 and 25%, respectively. Median (interquartile range) follow-up on ART was 3.9 (2.7-4.8) years. Given a person with pre-ART CD4 cell count below 100 cells/μl survives and maintains consistent viral load suppression on ART, there is over a 90% chance of reaching a CD4 cell count above 200 cells/μl by 3 years.