Access to HIV viral load testing and antiretroviral therapy switch practices: a multi-country prospective cohort study in sub-Saharan Africa.

BACKGROUND: poor access to HIV viral load (VL) testing prevents the timely monitoring of HIV treatment adherence and efficacy. Factors enabling clinical benefits of VL testing when added to local standards of care, can inform the development of more cost-effective routine VL scale-up plans. We compared antiretroviral therapy (ART) switch practices in 13 clinics across six countries, with full (N=8), phasing-in (N=3) or no onsite access (N=2) to VL.

METHODS: The analysis used data from the Pan-African Studies to Evaluate Resistance (PASER), observing virological and drug resistance outcomes among adults receiving first-or second-line ART between 2008 and 2015. Study plasma viral load (sVL) determined at baseline, every 12 months thereafter and at the time of switch served for retrospectively validating switch decisions, categorized into 'necessary', 'unecessary' and 'missed'. Virological failure was defined as two consecutive sVL≥ 1,000 HIV-RNA copies/mL.

RESULTS: 1,995 of the 2,420 (82.4%) study participants had continuous virological suppression during the median 30 months of follow-up. Among the 266 virological failures (11.0%), the proportion of necessary switches were similar in clinics with full (37%), phasing-in (25%) or no access (39%) to VL testing. Documented utilization of local VL results for the switch decision was associated with higher percentage of necessary switch (87.6% versus 67.9%). Shorter time to necessary switch was associated with higher rates of long-term viral suppression, regardless access to VL.

CONCLUSION: availability of HIV VL testing capacity does not systematically result in adequate switch practices or better virological outcomes. Systems supporting sufficient test demand, execution and actual utilization of results for patient management need strengthening.