Decentralization of viral load testing to improve HIV care and treatment cascade in rural Tanzania: Data from the Kilombero and Ulanga Antiretroviral Cohort

Abstract Introduction: Monitoring HIV viral load (VL) in people living with HIV (PLHIV) on antiretroviral therapy (ART) is recommended by the World Health Organization. Implementation of VL testing programs have been affected by logistic and organizational challenges. Here we describe the VL monitoring cascade in a rural setting in Tanzania and compare turnaround times (TAT) between an on-site and a referral laboratory. Methods In a nested study of the prospective Kilombero and Ulanga Antiretroviral Cohort (KIULARCO) we included PLHIV aged ≥ 15 years, on ART for ≥ 6 months after implementation of routine VL monitoring in 2017. We assessed proportions of PLHIV with a blood sample taken for VL, whose results came back, and who were virally suppressed (VL < 1000 copies/mL) or unsuppressed (VL ≥ 1000 copies/mL). We described the proportion of PLHIV with unsuppressed VL and adequate measures taken as per national guidelines and outcomes among those with low-level viremia (LLV; 100–999 copies/mL). We compare TAT between on-site and referral laboratories by Wilcoxon rank sum tests. Results From 2017 to 2020, among 4,454 PLHIV, 4,238 (95%) had a blood sample taken and 4,177 99 %) of those had a result. Of those, 3,683 (88%) were virally suppressed. In the 494 (12%) unsuppressed PLHIV, 425 (86%) had a follow-up VL (102 (24%) within 4 months and 158 (37%) had virologic failure. Of these, 103 (65%) were already on second-line ART and 32/55 (58%) switched from first- to second-line ART after a median of 7.7 months (IQR 4.7–12.7). In the 371 (9%) PLHIV with LLV, 327 (88%) had a follow-up VL. Of these, 267 (82%) resuppressed to < 100 copies/ml, 41 (13%) had persistent LLV and 19 (6%) had unsuppressed VL. The median TAT for return of VL results was 21 days (IQR 13–39) at the on-site versus 59 days (IQR 27–99) at the referral laboratory (p < 0.001) with PLHIV receiving the VL results after a median of 91 days (IQR 36–94; similar for both laboratories). Conclusion Robust VL monitoring is achievable in remote resource-limited settings. More focus is needed on care models for PLHIV with high viral loads to timely address results from routine VL monitoring.