I.G.M. van Valkengoed

Cost effectiveness analysis of a population based screening programme for asymptomatic Chlamydia trachomatis infections in women by means of home obtained urine specimens

Objectives: To evaluate the cost effectiveness of a systematic screening programme for asymptomatic Chlamydia trachomatis infections in a female inner city population. To determine the sensitivity of the cost effectiveness analysis to variation in the probability of developing sequelae. Methods: A decision tree was constructed to evaluate health effects of the programme, such as averted sequelae of chlamydial infection. Cost effectiveness from a societal perspective was estimated for screening by means of a ligase chain reaction on mailed, home obtained urine specimens, in a population with a C trachomatis test prevalence of 2.9%. An extensive sensitivity analysis was performed for the probability of sequelae, the percentage of preventable pelvic inflammatory disease (PID), and the discount rate. Results: The estimated net cost of curing one woman, aged 15–40 years, of a C trachomatis infection is US

Low diagnostic accuracy of selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population

1210. To prevent one major outcome (PID, tubal factor infertility, ectopic pregnancy, chronic pelvic pain, or neonatal pneumonia), 479 women would have to be screened. The net cost of preventing one major outcome is

Chlamydia trachomatis prevalence and sexual behaviour among female adolescents in Belgium.

15 800. Changing the probability of PID after chlamydial infection from 5% to 25% decreases the net cost per major outcome averted from

Disappointing performance of literature-derived selective screening criteria for asymptomatic Chlamydia trachomatis infection in an inner-city population

28 300 to

Notice of Redundancy

6380, a reduction of 78%. Results were less sensitive to variations in estimates for other sequelae. The breakeven prevalence of the programme ranges from 6.4% for the scenario with all probabilities for complications set at the maximum value to a prevalence of 100% for probabilities set at the minimum value. Conclusions: Systematic screening of all women aged 15–40 years for asymptomatic C trachomatis infections is not cost effective. Although the results of the analyses are sensitive to variation in the assumptions, the costs exceed the benefits, even in the most optimistic scenario.

UROGENITAL CHLAMYDIA TRACHOMATIS SEROVARS IN MEN AND WOMEN WITH A SYMPTOMATIC OR ASYMPTOMATIC INFECTION: AN ASSOCIATION WITH CLINICAL MANIFESTATIONS?

Objectives: To develop and validate selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population. Methods: 11 505 people, aged 15–40 years, registered in 16 general practices in Amsterdam were invited to return by mail a home obtained first void urine sample and a questionnaire. Participants were randomly allocated into a development group (75%) or a validation group (25%). C trachomatis infection was determined by the ligase chain reaction. In the development group a set of criteria was identified by means of stepwise logistic regression analysis. The diagnostic accuracy (area under the ROC curve; AUC) and sensitivity, and the corresponding percentage of people selected for screening were calculated. The criteria developed in this study were applied to the validation group. Results: The prevalence of asymptomatic C trachomatis infections among men was found to be 2.4% (1.7–3.0), and among women 2.8% (2.2–3.4). Screening men, based on Surinam/Antillean origin and painful micturition, yielded an AUC of 0.58 (0.55–0.60). Screening women, based on Surinam/Antillean origin, new sex partner in the previous 2 months, and unmarried/not cohabiting, yielded an AUC of 0.67 (0.65–0.69). Application of the criteria for men to the validation group yielded an AUC of 0.53 (0.48–0.57); by screening 10% of the men, 15% of the cases were detected. The AUC of the criteria for women in the validation group was 0.58 (0.54–0.61); by screening 51% of the women, 63% of the cases were detected. Conclusion: The prevalence of asymptomatic C trachomatis infections in Amsterdam is less than 3%. No suitable selective screening criteria for the general population could be identified.

Mailed, Home-Obtained Urine Specimens: a Reliable Screening Approach for Detecting Asymptomatic Chlamydia trachomatis Infections

OBJECTIVES To determine prevalence and risk factors of Chlamydia trachomatis among female secondary school students and to develop potential selective screening strategies. METHODS A cross sectional survey was conducted in the 17 school medical centres in Antwerp municipality, Belgium. All female students of forms 5 or 6, who were due for their medical check up during the school year 1996-7, were invited to participate. A self administered questionnaire on general and sexual behaviour, and a first void urine sample were collected. The urine specimen was tested for C trachomatis with ligase chain reaction assay, and positive tests were confirmed with polymerase chain reaction assays. RESULTS 2784 female students participated in the study. Their median age was 17, and 52% of them reported having sexual intercourse at least once. The prevalence of C trachomatis among sexually active women was 1.4%. Factors significantly associated with infection in multivariate analysis were number of lifetime partners, genital complaints of partner, type of secondary school, and a history of pregnancy. Selective screening of those women who are at highest risk for infection would have detected 90% of all infections, and require testing of 14% to 18% of the population. CONCLUSIONS The prevalence of C trachomatis was relatively low among female secondary school students in Antwerp, but unsafe sex practices were evident because of the high number of unplanned pregnancies. Selective screening strategies with a high sensitivity can be proposed, but should be assessed for acceptability, feasibility, and cost.

Determination of Chlamydia trachomatis Prevalence in an Asymptomatic Screening Population: Performances of the LCx and COBAS Amplicor Tests with Urine Specimens

BACKGROUND In an inner-city population with a low prevalence of Chlamydia trachomatis infection, selective screening may be indicated to increase the efficiency of screening. GOAL To evaluate the performance of sets of selective screening criteria for asymptomatic Chlamydia trachomatis infection in an inner-city population. The criteria were derived from reports of studies carried out in various settings. STUDY DESIGN A total of 5714 women age 15 to 40 years living in Amsterdam were invited for a screening based on home-obtained urine specimens. Criteria identified from the literature were applied to the screening population. A calculated area under the receiver-operator characteristic curve (AUC) of greater than 0.75 was considered a good measure of diagnostic accuracy. RESULTS Of the four sets of criteria, selection based on the following determinants showed the highest diagnostic accuracy: younger than 25 years, being unmarried, number of partners during the previous 6 months, Surinam or Antillean origin (black), and vaginal douching (AUC, 0.67; 95% CI, 0.65-0.69). Selection based on age alone showed an AUC of 0.57 (95% CI, 0.55-0.69). CONCLUSION The performance of selective screening criteria for asymptomatic C trachomatis infection in an inner-city population in Amsterdam was insufficient to recommend its implementation in practice.

Systematische opsporing van infecties met chlamydia trachomatis bij mannen en vrouwen zonder klachten in de huisartspraktijk met behulp van per post verstuurde urinemonsters

The hanging committee of Sexually Transmitted Infections wishes to announce that two published papers by van Valkengoed et al 2 exhibit a degree of overlap. Specifically, the female patients are the same in both papers. They are indistinguishable from the point of population size (5714), age (15–40), setting, participation rate (51%), chlamydia prevalence rate (2.8%; CI 2.1–3.4%), and the number of women excluded because of never having been sexually active (125). There is also a certain degree of overlap between the two papers in the introduction, methods, results, and discussion sections.