True durability: HIV virologic suppression in an urban clinic and implications for timing of intensive adherence efforts and viral load monitoring

Abstract

Although the majority of HIV-infected patients who begin potent antiretroviral therapy should expect long-term virologic suppression, the realities in practice are less certain. Durability of viral suppression was examined to define the best timing of targeted adherence strategies and intensive viral load monitoring in an urban clinic population with multiple challenges to ART adherence. We examined the risk of viral rebound for patients who achieved two consecutive viral loads lower than the lower limit of quantification (LLOQ) within 390 days. For 791 patients with two viral loads below the LLOQ, viral rebound >LLOQ from the first viral load was 36.9 % (95 % CI 32.2-41.6) in the first year, 26.9 % (95 % CI 21.7-32.1) in the year following one year of viral suppression, and 24.6 % (95 % CI 18.4-30.9) in the year following 2 years of viral suppression. However, for patients with CD4 ≥300 cells/µl who had 3-6 years of virologic suppression, the risk of viral rebound was very low. At the population level, the risk of viral rebound in a complex urban clinic population is surprisingly high even out to 3 years. Intensified monitoring and adherence efforts should target this high risk period. Thereafter, confidence in truly durable virologic suppression is improved.

Fig. 1

Top panels Probability of viral rebound above lower limit of quantification (LLOQ) where the right panels is the cohort as a whole and the left panels is stratified by CD4 groups. Bottom panels Probability of viral rebound above 200 where the right panels is the cohort as a whole and the left panels is stratified by CD4 groups

Fig. 2

Yearly probability of viral rebound (left) HIV >lower limit of quantification (LLOQ) and (right) HIV >200. Dashed line square CD4 <300, Solid line circle CD4 ≥300