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

Abstract

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.

Programmatic evaluation of feasibility and efficiency of at birth and 6-week, point of care HIV testing in Kenyan infant

“…Our total sample was relatively small; and we observed very few positive infants. Outcomes for HIV-positive infants-including timing of ART initiation and long term outcomes for HIV-positive infants-are an important aspect of evaluations for testing methods [31,32]. While very low yield of positive infants' results reflect the high coverage of antenatal ART and will likely continue to decrease, globally, as we strive towards elimination of mother-to-child transmission, it does prevent assessment of these critical impact data and forces us to rely on proxy measures such as timing of caregiver notification of results.…”

“…POC diagnostic technologies such as GeneXpert HIV-1 Qual [ 15 ] and Alere m-PIMA [ 16 ] are cartridge-based tests that can be processed at the hospital by trained clinical or laboratory staff and can result in more rapid turnaround times of results, more infants being identified as HIV-positive and more infants initiated on ART at younger ages than traditional testing strategies [ 17 – 22 ]. Studies have shown high sensitivity and specificity of POC testing and found that POC implementation is feasible in hospital-based settings in Kenya [ 23 , 24 ], South Africa [ 18 , 25 – 27 ], Mozambique [ 28 ], and Tanzania [ 29 ]; is acceptable to providers [ 26 ] and patients [ 30 ]; and may be a cost-effective option for EID [ 31 , 32 ]. Based on the promising evidence supporting POC, the World Health Organization (WHO) conditionally recommended the introduction of POC for EID in 2016 [ 33 ].…”

Costs and cost-effectiveness of HIV early infant diagnosis in low- and middle-income countries: a scoping review

“…Unit costs per test are reported in Table 1. Seven studies reported unit costs for PoC assays [13,40,[50][51][52][53][54], 13 for laboratory testing [13,24,38,39,41,44,46,[50][51][52][53][54][55], two for rapid testing [41,56], and one for unspecified NAT [57] Variation in unit costs for PoC assays may be explained by inclusion of capital costs. Costs for m-PIMA that included equipment costs were > 20 USD higher than those that did not include equipment costs.…”

“…Few studies assessed the same intervention or reported costs in the same way, making comparison of costs across studies challenging. Most studies evaluated costs or cost-effectiveness of EID testing approaches including four studies on PoC EID [45,50,52,53], three on birth testing [24,44,59], one study that assessed both PoC and improvements to centralized EID [51], one that reported costs of confirmatory testing in EID programs [54], one of added screening of mothers at 6-week infant immunization visits with referral to EID for infants at risk of acquiring HIV [57], and one of rapid antibody screening to rule out negative infants before NAT [41].…”

“…Lifetime PoC EID testing costs were estimated at 264 and 470 USD per infant in Zimbabwe [51,52] and 1.2-4.7 million USD total program costs [50,53] in representative sub-Saharan African countries. Modelled total PoC EID program costs were slightly higher for m-PIMA compared to GeneXpert ® but similar for settings with low and high PMTCT coverage [50,53].…”