Clinical outcomes in the era of test and treat among children living with HIV: A retrospective before /after study in Zambia

Benson M Hamooya^1*Simon Mutembo²Lukundo Siame¹Matenge Mutalange¹Chilala Cheelo¹Kingsley Kamvuma¹Brian Muyunda³Keith Mweebo³Nzali Kancheya³Callistus Kaayunga⁴Morgan Sakala⁵Johanzi Mvula⁵Salazeh Kunda⁵Shem Kabesha³Clive Banda⁵Derrick Sikaulu⁵Isaac Fwemba⁶Sepiso K Masenga^1*

• ¹Mulungushi University School of Medicine and Health Sciences, Livingstone, Zambia
• ²International Vaccine Access Center, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States
• ³Centers for Disease Control and Prevention, DGHT, Lusaka, Zambia
• ⁴Other
• ⁵Provincial Health Office, Ministry of Health, Choma, Zambia
• ⁶University of Zambia, Lusaka, Zambia

Background: Initiating antiretroviral therapy (ART) immediately after HIV diagnosis can reduce morbidity and mortality in children living with HIV (CLHIV), particularly when they are retained in care. In Zambia, the retention rate of CLHIV was unknown. This study aimed to determine retention rates and clinical outcomes following implementation of the test-and-treat (ATT) program. Methods: We conducted a retrospective before/after study in 42 health facilities across 12 districts of Southern Zambia. Case files of CLHIV initiated on ART before test-and-treat (BTT; January 2014–July 2016, n=405) and after ATT implementation (August 2016–October 2020, n=579) were reviewed. Demographic, laboratory, and clinical data were abstracted into REDCap. The primary outcome was retention, defined as consistent attendance or engagement at ART clinics at 3, 6, 12, 24, and ≥24 months post-initiation. Descriptive statistics and logistic regression were applied. Results: Among 984 CLHIV, the median age (IQR) was 60 months (22, 100), and 52.3% (n=515) were female. Overall retention at 24 months was 82.0% (n=807; 95% CI: 79.5–84.4). Retention was significantly higher in the ATT cohort compared to BTT (91.0% vs. 69.1%, p<0.001). Children in the BTT group had higher transfer-out (19.0% vs. 4.8%, p<0.001) and loss-to-follow-up (11.1% vs. 3.8%, p<0.001) rates. Clinical outcomes improved, with WHO stage 1 rising from 83% to 98% among those retained at end of follow-up. In multivariable analysis, factors positively associated with retention included enrollment in the ATT cohort (aOR 4.98; 95% CI: 4.06–6.11) and use of dolutegravir (DTG)-based regimens (aOR 2.66; 95% CI: 1.05–6.72). In contrast, female sex (aOR 0.80; 95% CI: 0.67–0.95), longer time from HIV diagnosis to ART initiation (aOR 0.99; 95% CI: 0.99–0.99), and advanced WHO clinical stage (stage 3: aOR 0.68; 95% CI: 0.52–0.90; stage 4: aOR 0.30; 95% CI: 0.19–0.48) were negatively associated with retention. Conclusion: Retention was significantly higher in children initiated on ART under ATT and those receiving DTG-based regimens. Female sex, delayed ART initiation, and advanced disease stage predicted lower retention. These findings highlight the importance of immediate ART initiation to improve retention and outcomes for CLHIV in resource-limited settings.