Strengthening Existing Laboratory-Based Systems vs. Investing in Point-of-Care Assays for Early Infant Diagnosis of HIV: A Model-Based Cost-Effectiveness Analysis.

BACKGROUND: To improve early infant HIV diagnosis (EID) programs, options include replacing laboratory-based tests with point-of-care (POC) assays or investing in strengthened systems for sample transport and result return. SETTING: We used the CEPAC-Pediatric model to examine clinical benefits and costs of 3 EID strategies in Zimbabwe for infants 6 weeks of age. METHODS: We examined (1) laboratory-based EID (LAB), (2) strengthened laboratory-based EID (S-LAB), and (3) POC EID (POC). LAB/S-LAB and POC assays differed in sensitivity (LAB/S-LAB 100%, POC 96.9%) and specificity (LAB/S-LAB 99.6%, POC 99.9%). LAB/S-LAB/POC algorithms also differed in: probability of result return (79%/91%/98%), time until result return (61/53/1 days), probability of initiating antiretroviral therapy (ART) after positive result (52%/71%/86%), and total cost/test ($18.10/$30.47/$30.71). We projected life expectancy (LE) and average lifetime per-person cost for all HIV-exposed infants. We calculated incremental cost-effectiveness ratios (ICERs) from discounted (3%/year) LE and costs in $/year-of-life saved (YLS), defining cost effective as an ICER <$580/YLS (reflecting programs providing 2 vs. 1 ART regimens). In sensitivity analyses, we varied differences between S-LAB and POC in result return probability, result return time, ART initiation probability, and cost. RESULTS: For infants who acquired HIV, LAB/S-LAB/POC led to projected one-year survival of 67.3%/69.9%/75.6% and undiscounted LE of 21.74/22.71/24.49 years. For all HIV-exposed infants, undiscounted LE was 63.35/63.38/63.43 years, at discounted lifetime costs of $200/220/240 per infant. In cost-effectiveness analysis, S-LAB was an inefficient use of resources; the ICER of POC vs. LAB was $830/YLS. CONCLUSIONS: Current EID programs will attain greater benefit from investing in POC EID rather than strengthening laboratory-based systems.

Estimating the Cost of Point-of-Care Early Infant Diagnosis in a Program Setting: A Case Study Using Abbott m-PIMA and Cepheid GeneXpert IV in Zimbabwe.

BACKGROUND: Point-of-care early infant diagnosis (POC EID) increases access to HIV test results and shortens time to result-return and antiretroviral therapy initiation, as compared to central laboratory-based EID. However, to scale-up POC EID, governments need more information about programmatic costs. METHODS: We evaluated POC EID costs from a health systems perspective. Our primary analysis assessed the Abbott m-PIMA and 2 versions of the Cepheid GeneXpert IV platforms-with a solar battery or gel battery-used in Zimbabwe, with instrument purchase. We also included the following 2 scenarios with zero upfront equipment purchase: (1) m-PIMA using a reagent rental model, with an all-inclusive price when the buyer commits to an average testing volume, and (2) GeneXpert IV, reflecting contexts where GeneXpert is already in place for tuberculosis diagnosis or HIV viral load monitoring. We collected data from project expenditures, observations of health workers, and from government salary scales. We calculated cost per EID test based on number of EID tests performed on each machine per day. RESULTS: The cost per successfully completed test was $44.55 for m-PIMA with platform purchase and $25.89 for m-PIMA reagent rental. Costs for GeneXpert IV with platform purchase were $25.70 using a solar battery, $25.29 using a gel battery, and $23.85 under a scenario assuming no equipment costs. In our primary analyses, materials costs comprised 73%-74% total costs, equipment 14%-20%, labor 5%-8%, training 1%, facility upgrades 1%, and monitoring 1%. CONCLUSIONS: As countries consider scaling up POC EID, these data are important for budgeting and planning.