Background: When people with HIV (PWH) on integrase strand transfer inhibitors (INSTIs) have a detectable viral load (VL) after prior viral suppression (VS), a follow-up test within 8 weeks to confirm status is recommended. It is unclear if health system processes for re-testing differ across patient groups.

Objective: Describe timing of follow-up testing and re-suppression after first detectable VL measurement by age, sex, race, region.

Methods: We used data from the North American AIDS Cohort Collaboration on Research and Design, a clinical cohort consortium of adult PWH. Eligible PWH enrolled from 2012 to 2022, engaged in HIV care, initiated an INSTI, achieved VS (VL <200 copies/mL), and had detectable VL (≥200 copies/mL). Index date was first detectable VL, post-VS (median VS: 486 days). Primary outcomes were 6- and 24-mo incidence of follow-up VL testing and virologic re-suppression (<200 copies/mL) estimated using the Aalen–Johansen estimator.

Results: Among 15449 PWH, 74% had a second VL measurement and 66% resuppressed within 6 mo; at 24 mo, estimates were 94% and 88%, respectively. Outcomes were similar by sex and race, but only 68% (95%CI 66-70) of PWH age 25-34 received a follow-up test within 6-mo of index VL, compared to 79% (95%CI 77-80) age >65. At 24 mo, 91% (95%CI 89-92) of PWH age >65 achieved VS compared to only 81% (95%CI 80-83) age 25-34 (Figure). Regions included Canada (<1%) and the US Northeast (32%), South (35%), West (26%), Midwest (7%). In the US, the West had the lowest proportion of second VL test (72%, 95%CI 70-73) or re-suppression (64%, 95%CI 62-66) by 6-mo; at 24-mo, primary outcomes were similar by region. Across all time points, Canadian PWH had the lowest proportion of second VL test and re-suppression, but sample size was limited.

Conclusions: There may be age-based or regional differences in care following a detectable VL in PWH taking INSTIs. Specific groups may benefit from point of care VL testing to minimize time unsuppressed.