Cost-effectiveness of a dual non-treponemal/treponemal syphilis point-of-care test to prevent adverse pregnancy outcomes in sub-Saharan Africa.

BACKGROUND: A dual nontreponemal/treponemal point-of-care test (Dual-POC) that simultaneously detects both nontreponemal and treponemal antibodies has been developed and evaluated. In this study, we compare the health and economic outcomes of the new test with existing syphilis tests/testing algorithms in a high prevalence setting. METHODS: We used a cohort decision analysis model to examine 4 testing/screening algorithms; the Dual-POC test, the laboratory-based rapid plasma reagin and Treponema pallidum haemagglutination assay (RPR+TPHA) algorithm, an onsite RPR testing, and point-of-care treponemal immunochromatographic strip (ICS) testing. Outcomes included miscarriage, stillbirth, congenital syphilis, low birth weight, and neonatal death. Disability-adjusted life-years were estimated for all health outcomes. The analytic horizon was the life expectancy for the mother and child. RESULTS: For a cohort of 1000 pregnant women in a historically high syphilis prevalence population (10% infected and 15% previously infected), the model predicted a total of 39 adverse pregnancy outcomes if no serologic screening were performed; 13 for the laboratory-based RPR+TPHA; 11 for the on-site RPR strategy; 5 for the Dual-POC strategy; and 2 for the ICS strategy. On the basis of assumption that the cost of ICS and the Dual-POC tests were the same, the ICS strategy was the most cost saving (saved $30,000) followed by the Dual-POC strategy (saved $27,000). CONCLUSIONS: The dual-POC test may help save cost in resource-poor settings where disease prevalence (and loss to follow-up) is high, while substantially reducing overtreatment.

Serologic testing for syphilis in the United States: a cost-effectiveness analysis of two screening algorithms.

BACKGROUND: The introduction of automated treponemal enzyme immunoassays and chemiluminescence assays (EIA/CA) tests has led some laboratories in the United States to use new syphilis screening algorithms that start with a treponemal test. We compared the economic and health outcomes of this new algorithm with the standard algorithm from the perspective of the United States health system. METHODS: We used a cohort decision analysis to estimate the expected costs and effects (including follow-ups and overtreatment) of the 2 algorithms from a health-care system perspective. In the standard algorithm, rapid plasma reagin (RPR) is followed (if reactive) by EIA/CA (Nontreponemal-First). In the new algorithm, EIA/CA is followed (if reactive) by RPR. If the RPR is negative, Treponema pallidum passive particle agglutination assay (TP-PA) test is used (Treponemal-First). RESULTS: For a cohort of 200,000 individuals (1000 current infections and 10,000 previous infections), the net costs were $1.6 m (Treponemal-First) and $1.4 m (Nontreponemal-First). The Treponemal-First option treated 118 more cases (986 vs. 868) but resulted in a substantially higher number of follow-ups (11,450 vs. 3756) and overtreatment (964 vs. 38). Treating the additional 118 cases might prevent 1 case of tertiary syphilis. The estimated cost-effectiveness ratios were $1671 (Treponemal-First) and $1621 (Nontreponemal-First) per case treated. The overtreatment was a function of the specificity of the EIA/CA and the lack of independence of EIA/CA and TP-PA. CONCLUSION: The Treponemal-First option costs slightly more and results in more unnecessary treatment.

The tale of two serologic tests to screen for syphilis--treponemal and nontreponemal: does the order matter?

BACKGROUND: Standard syphilis screening involves an initial screening with a nontreponemal test and confirmation of positives with a treponemal test. However, some laboratories have reversed the order. There is no detailed quantitative and qualitative evaluation for the order of testing. In this study, we analyzed the health and economic outcomes of the order of testing for the 2 serologic tests used in syphilis screening under pure screening settings. METHODS: We used a cohort decision analysis to examine the health and economic outcomes of the screening algorithms for low and high prevalence settings. The 2-step algorithms were nontreponemal followed by treponemal (Nontrep-First) and treponemal followed by nontreponemal (Trep-First). We included the 1-step algorithms (treponemal only [Trep-Only] and an on-site nontreponemal only [Nontrep-Only]) for comparison. We estimated overtreatment rates and the number of confirmatory tests required for each algorithm. RESULTS: For a cohort of 10,000 individuals, our results indicated that the overtreatment rates were substantially higher (more than 3 times) for the 1-step algorithms, although they treated a higher number of cases (over 15%). The 2-step algorithms detected and treated the same number of individuals. Among the 2-step algorithms, the Nontrep-First was more cost-effective in the low prevalence setting ($1400 vs. $1500 per adverse outcome prevented) and more cost-saving ($102,000 vs. $84,000) in the high prevalence setting. CONCLUSIONS: The difference in cost was largely due to the substantially higher number of confirmatory tests required for the Trep-First algorithm, although the number of cases detected and treated was the same.

Cost-effectiveness of on-site antenatal screening to prevent congenital syphilis in rural eastern Cape Province, Republic of South Africa.

OBJECTIVES: On-site screening and same-day treatment of maternal syphilis in underresourced settings can avert greater numbers of congenital syphilis cases, but health outcomes and associated costs must be evaluated jointly. METHODS: We used decision analysis to estimate the incremental cost-effectiveness of two on-site antenatal syphilis screening strategies to avert congenital infections-qualitative RPR (on-site RPR) and treponemal immunochromatographic strip assay (on-site ICS)-compared to the current practice (off-site RPR/TPHA). FINDINGS: With antenatal active syphilis prevalence of 6.3%, the incremental cost-effectiveness of on-site ICS in averting congenital infections was estimated to be USD104, averting 82% of cases expected in absence of a program. The incremental cost-effectiveness of off-site RPR/TPHA was USD82 but would avert only 55% of congenital syphilis cases. On-site RPR was dominated by the other screening strategies. CONCLUSIONS: In settings of high maternal syphilis prevalence, on-site antenatal screening with ICS is a cost-effective approach to reduce the incidence of congenital syphilis.

Analysis of the operational costs of using rapid syphilis tests for the detection of maternal syphilis in Bolivia and Mozambique.

OBJECTIVE: The objective of this study was to compare the costs of antenatal syphilis screening with the rapid plasma reagin (RPR) test and the immunochromatographic strip (ICS) test in low-resource settings. GOAL: The goal of this study was to assess the costs of introducing rapid syphilis tests to reduce maternal and congenital syphilis. STUDY DESIGN: Cost data were collected from participating study hospitals and antenatal clinics during 4 field visits to the 2 countries in 2003 and 2004. Health utilization outcome data on the number of women screened and treated routinely during the demonstration projects were used with unit cost data to estimate the incremental costs and average cost per woman screened and treated for maternal syphilis. RESULTS: In Mozambique, the average cost per woman screened was U.S. $0.91 and U.S. $1.05 for the RPR and ICS tests, respectively. In Bolivia, the average cost of screening was U.S. $1.48 and U.S. $1.91 using the RPR and ICS test, respectively. In health centers without laboratories, the cost per woman screened using the ICS test ranged from U.S. $1.02 in Mozambique to U.S. $2.84 in Bolivia. CONCLUSIONS: It is feasible to introduce rapid syphilis testing in settings without laboratory services at a small incremental cost per woman screened. In settings with laboratories, the cost of ICS is similar to that of RPR.

On-site rapid antenatal syphilis screening with an immunochromatographic strip improves case detection and treatment in rural South African clinics.

OBJECTIVES: Congenital syphilis is a significant cause of adverse pregnancy outcomes. In South Africa, rural clinics perform antenatal screening offsite, but unreliable transport and poor client follow up impede effective treatment. We compared 3 syphilis screening strategies at rural clinics: on-site rapid plasma reagin (RPR), on-site treponemal immunochromatographic strip (ICS) test, and the standard practice offsite RPR with Treponema pallidum hemagglutination assay (RPR/TPHA). METHODS: Eight rural clinics performed the on-site RPR and ICS tests and provided immediate treatment. Results were compared with RPR/TPHA at a reference laboratory. Chart reviews at 8 standard practice clinics established diagnosis and treatment rates for offsite RPR/TPHA. FINDINGS: Seventy-nine (6.3%) of 1,250 women screened on-site had active syphilis according to the reference laboratory. The on-site ICS resulted in the highest percentage of pregnant women correctly diagnosed and treated for syphilis (89.4% ICS, 63.9% on-site RPR, 60.8% offsite RPR/TPHA). The on-site RPR had low sensitivity (71.4% for high-titer syphilis). The offsite approach suffered from poor client return rates. One percent of women screened with the ICS may have received penicillin unnecessarily. There were no adverse treatment outcomes. CONCLUSIONS: The on-site ICS test can reduce syphilis-related adverse outcomes of pregnancy through accurate diagnosis and immediate treatment of pregnant women with syphilis.