Cost effectiveness of screening for Chlamydia trachomatis:: a review of published studies

Objective: Screening for Chlamydia trachomatis in the lower genital tract may contribute to the prevention of pelvic inflammatory disease in women. The purpose of this review was to critically appraise, and summarise studies of the cost effectiveness of screening for C trachomatis. Methods: A literature search was conducted on Medline and in Health Star from 1990-2000. Keywords were C trachomatis, screening, cost effectiveness. Bibliographies of reviewed articles were also searched. The population studied was asymptomatic sexually active women under 30 years of age in a primary care setting. The intervention assessed was screening for lower genital tract infection with C trachomatis and the outcomes studied were cases of C trachomatis detected, cases of PID prevented, and associated costs. Studies were assessed using the Drummond criteria for economic evaluations. They were assessed qualitatively as they were too heterogeneous to allow quantitative analysis. Results: 10 studies were included. All were modelled scenarios and all found screening to be more cost effective than simply testing symptomatic women, although all were based on probabilities that were assumed. Six of the studies focused on DNA based testing, three of them using urine. The models showed screening to be cost effective at prevalences of 3.1-10.0%, and cost saving (overtesting symptomatic women) at a prevalence as low as 1.1%, if age was used as a selection factor and DNA based tests were used in urine samples. Conclusions: At the prevalence of infection expected in the target population, all studies suggest screening is cost effective. However, the assumptions used in the models have been difficult to confirm and there is a need for more data, particularly on the risk of complications in women with asymptomatic lower tract infection.