Screening women for chlamydia trachomatis in family planning clinics: the cost-effectiveness of DNA amplification assays.

Abstract

Highly sensitive and specific DNA amplification assays are available for use on cervical and urine specimens. These new tests have the potential to identify more chlamydial infections than the commonly used enzyme immunoassay and DNA probe tests, yet they are more expensive. This study sought to assess the cost effectiveness of cell culture, enzyme immunoassay (EIA), DNA probe (Pace 2), polymerase chain reaction (PCR) of cervical and urine specimens, and ligase chain reaction (LCR) of cervical and urine specimens as screening tools for Chlamydia trachomatis in asymptomatic women younger than 30 years of age attending family planning clinics. Program costs; medical cost savings of prevented sequelae in women, male sex partners, and infant; and number of prevented cases of pelvic inflammatory disease (PID), neonatal infections, and male sex partner urethritis and epididymitis were modeled in a decision analysis conducted from a health care system perspective. Results are expressed for a cohort of 18,000 women. If no screening for C. trachomatis were conducted in Maryland, 497 cases of PID would develop, costing $2.2 million in future medical costs. Use of EIA to detect chlamydial infection would prevent 240 cases of PID and save $887,000 over no screening. Alternatively, use of DNA amplification assays on urine specimens would prevent up to an additional 66 cases and save $287,100 over EIA. Use of LCR on cervical specimens would prevent at least 13 additional cases of PID over the urine-based assays, but would cost $3,005 for each additional case prevented. In women receiving routine pelvic examinations, LCR of cervical specimens would prevent the most disease and provide the highest cost savings. In women not receiving routine pelvic examinations, use of LCR on cervical specimens would prevent the most disease but would cost approximately $28,000 per additional case of PID prevented over DNA amplification of urine. Compared with EIA screening, the strategy with the lowest program costs, a screening strategy that combines use of DNA amplification on cervical specimens in women receiving pelvic examinations, and DNA amplification of urine in women with no medical indications necessitating a pelvic examination, prevents the most cases of PID and provides the highest cost savings. With enhanced sensitivity over the other diagnostic assays and with the use of noninvasive specimen collection, DNA amplification assays should be implemented as cost-effective components of a screening program for C. trachomatis.