Abstract and Introduction
Abstract
Objectives To compare the effectiveness and cost-effectiveness of a promising new point-of-care (POC) chlamydia test with traditional nucleic acid amplification testing (NAAT), and to determine the characteristics that would make a POC test most cost-effective.
Methods A decision tree was constructed to model chlamydia screening visits to a sexually transmitted disease clinic by a hypothetical cohort of 10 000 women. The model incorporated programmatic screening costs, treatment costs and medical costs averted through prevention of pelvic inflammatory disease (PID) and its sequelae. Parameter values and costs were estimated for each node in the decision tree based on primary data, published data and unpublished health data.
Results For the base-case scenario (POC sensitivity 92.9%; 47.5% of women willing to wait 40 min for test results; test cost $33.48), POC was estimated to save US$5050 for each case of PID averted compared with NAAT. One-way sensitivity analyses indicated that POC would dominate NAAT if the POC test cost is <US$41.52 or if POC sensitivity is ≥87.1%. In a probabilistic sensitivity analysis (Monte Carlo simulations, 10 000 iterations), 10.8% of iterations indicated that the POC strategy dominated the NAAT strategy. The mean incremental cost-effectiveness ratio indicated that the POC strategy would save US$28 in total, and avert 14 PID cases.
Conclusions A promising new chlamydia POC test is likely to be cost-effective compared with traditional NAAT. The POC test sensitivity, cost and proportion of women willing to wait for the POC test result are key elements to determining the cost-effectiveness of any new POC test strategy.
Introduction
Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection (STI) in the USA, with >2 800 000 new cases estimated to occur annually. In untreated women, chlamydia infection can result in pelvic inflammatory disease (PID), which can cause serious and costly sequelae (infertility, ectopic pregnancy and chronic pelvic pain). Since the majority of chlamydia infections in women are asymptomatic, tubal damage can occur without her knowledge.
With the advent of nucleic acid amplification tests (NAATs), which can use non-invasive specimens and have high sensitivity and specificity, improved detection and treatment of chlamydia infection has been possible. However, these laboratory tests involve a delay between specimen submission and receipt of test results. This delay may lead to overtreatment (if patients are treated presumptively at their initial visit), postponed treatment (if the follow-up visit occurs days/weeks later), or even lack of treatment (if patients are lost to follow-up).
Recently, several companies have developed point-of-care (POC) tests that provide rapid results for the detection of chlamydia at the index visit. This can dramatically reduce the time between testing and treatment, as well as increase treatment rates. However, sensitivities of the three US Food and Drug Administration-approved POC chlamydia tests (25%–65%) preclude more widespread use in clinical settings. Nevertheless, POC tests can be beneficial in settings where patients do not reliably return for treatment. Based on focus group discussions with clinicians, opinion leaders and public health professionals, and a recent clinician survey, an ideal POC test should have ≥90% sensitivity, require ≤30 min to process, and cost ≤US$20.
We conducted a comparative effectiveness research (CER) study to examine differences in costs and outcomes between a promising new chlamydia POC test in development and traditional chlamydia NAATs. We also evaluated the characteristics that would result in making future POC tests more cost-effective than NAATs.