Cost-effectiveness of screening swab or urine specimens for Chlamydia trachomatis from young Canadian women in Ontario

Background. Undetected and untreated Chlamydia trachomatis infections can r esult in a significant health burden. Diagnostic testing refers to tests pe rformed on patients with symptoms, whereas screening refers to testing spec imens in asymptomatic patients. The goal of diagnostic testing and screenin g programs are early identification of infections to prevent upper tract in fection and transmission to other partners. Goal. To compare the costs and outcomes of alternative diagnostic testing a nd screening programs for women ages 15 to 24 years in the province of Onta rio, Canada. Study Design: Using outcome probabilities from the literature and a consens us group, together with the costs from insurance billing, a decision analyt ic model was constructed to determine the baseline risk of C trachomatis an d related sequelae. Seven diagnostic testing and screening programs were co mpared over a 10-year period. The programs compared included the use of nuc leic acid amplification assays collected from urine or endocervical swab sp ecimens. Results: Largely because of lower sensitivity the urine-based testing or sc reening programs were dominated by the swab-based programs. The move from s wab-based testing to a swab-based screening program for high-risk women cos ts $1873 per case of C trachomatis averted. Expanding the program further t o include all women in Ontario between 15 and 24 years of age is considerab ly more costly at $5990 per case averted. Conclusions: It is more costly and more effective to screen and treat high- risk women ages 15 to 24 years for C trachomatis than to perform only swab- based diagnostic testing on symptomatic women. Expanding the screening prog ram to include all women ages 15 to 24 years is considerably more expensive and only moderately more effective than screening only high-risk women.