Cost-Effectiveness of a Blended Learning Training Approach for Health Care Workers Conducting HIV Index Case Testing in Malawi: Secondary Economic Analysis of a Cluster-Randomized Controlled Trial

BACKGROUND: Index case testing (ICT) is an effective strategy for HIV case finding, but implementation in low- and middle-income countries (LMICs) is often limited by cost and logistical challenges. Traditional ICT training-centralized and in-person-is costly, disrupts service delivery, and varies in quality. OBJECTIVE: This study evaluates the cost-effectiveness of a blended learning (BL) implementation package designed to build health care worker capacity for ICT, combining tablet-guided teaching and practice sessions, phone-based feedback, and tablet-guided continuous quality improvement, compared with standard of care (SOC) training. METHODS: The Package of Resources for Assisted Contact Tracing: Implementation, Costs, and Effectiveness (PRACTICE) cluster-randomized controlled trial included 33 clusters in southern Malawi from May 2022 to September 2023, randomized 2:1 to SOC (n=22) or SOC + BL implementation package (n=11). Our cost-effectiveness analysis, from the health system perspective, used microcosting, time-and-motion assessments, and observed trial outcomes. The decision tree model estimated total program costs, contact testing outcomes, and incremental cost-effectiveness ratios (ICERs) per contact tested and per person diagnosed with HIV across 1 year of implementation. Sensitivity analyses assessed parameter uncertainty, and a scenario analysis modeled a nationwide scale-up under a decentralized, Ministry of Health-led approach. RESULTS: Our model simulated 100,000 index clients eligible for contact elicitation over 1 year across 2 districts (50,000 per arm). The BL implementation package arm yielded 891 additional contacts tested and 54 more HIV diagnoses. The ICERs were US $125 per contact tested and US $2045 per person diagnosed with HIV; excluding training development costs reduced these to US $69 and US $1136, respectively. Nationwide scale-up under a Ministry of Health-led model further reduced ICERs to US $43 per contact tested and US $698 per person diagnosed with HIV. Probabilistic sensitivity analyses showed the BL implementation package was cost-effective in most simulations. CONCLUSIONS: The BL implementation package improved ICT delivery and HIV case finding. Scenario analyses suggested that a decentralized, government-led scale-up could substantially reduce costs and may represent an efficient case-finding strategy, particularly in Malawi's mature epidemic. BL implementation packages provide a scalable, system-integrated, cost-effective approach that could strengthen health care worker capacity across other service delivery areas in low-resource settings. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2023-077706.