See the updated review, "Screening for Chlamydial Infection: A Focused Evidence Update for the U.S. Preventive Services Task Force"

This publication is provided for historical reference only and the information may be out of date.

Cover of Screening for Chlamydial Infection

Screening for Chlamydial Infection

Systematic Evidence Reviews, No. 3

, MD, MPH, , MD, MPH, Cost Section, and , MD, MS.

Oregon Health Sciences University Evidence-based Practice Center
Rockville (MD): Agency for Healthcare Research and Quality (US); .
Report No.: 01-S003
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Structured Abstract

Objectives:

To examine data on the effectiveness of screening for chlamydial infection by a physician or other health care professional. Specifically, we examine the evidence on the effectiveness of screening strategies in nonpregnant women, pregnant women, and men; the accuracy of tests used for screening; and evidence that early treatment of chlamydial infection improves health outcomes. This review updates the literature since the last recommendation of the U.S. Preventive Services Task Force (USPSTF) published in 1996.

Search Strategy:

We searched the topic of chlamydia in the MEDLINE, HealthSTAR, and Cochrane Library databases from January 1994 to November 1999, and supplemented the search by use of reference lists of relevant articles and from experts in the field. Cost studies were searched in the same databases from January 1989 to November 1999.

Selection Criteria:

A single reader reviewed all English abstracts. Papers were selected for full review if they were about Chlamydia trachomatis genitourinary infections in non-pregnant women, pregnant women, or men and were relevant to key questions in the analytic frameworks or related to cost. Papers published before 1994 were cited if they were important to the interpretation of more recent papers. Investigators read the full-text version of the retrieved papers and applied additional eligibility criteria. For all topics, we excluded articles if they did not provide sufficient information to determine the methods for selecting subjects and for analyzing data.

Data Collection and Analysis:

We systematically reviewed 3 types of studies about screening in nonpregnant women that relate to 3 key questions: (1) studies about the effectiveness of screening programs in reducing prevalence rates of infection, (2) studies about risk factors for chlamydial infection in women, and (3) studies about chlamydia screening tests in women. Our search found too few studies on pregnant women to create evidence tables, although pertinent studies are described in the text of the report. We systematically reviewed 2 types of studies about screening in men: (1) studies about prevalence rates and risk factors for chlamydial infection for men and (2) studies about chlamydia screening tests in men. We systematically reviewed cost studies related to screening women. We restricted our review to cost-effectiveness and cost-benefit studies. We reviewed 2 types of studies: (1) studies in which selective to universal screening were compared and (2) studies in which chlamydia screening tests were compared.

Main Results:

Nonpregnant women: The initiation of screening programs in multiple settings and communities is associated with declines in chlamydial infection prevalence rates in the populations they serve. Changes in population prevalence rates have not been well documented since few studies have employed a representative population sample. Age continues to be the best predictor of chlamydial infection in women, with most studies evaluating cutoffs at age younger than 25 years. Other risk factors may be useful predictors, but these are likely to be population specific. To determine the accuracy of screening tests for women, we retrieved and critically reviewed 33 papers on test performance. Results indicate that when DNA amplification tests are used, cervical swab specimens and first void urine specimens have similar and have better sensitivity than endocervical culture. The results of a randomized controlled trial conducted in a large health maintenance organization indicate that screening women selected by a set of risk factors reduces the incidence of pelvic inflammatory disease (PID) for a 1-year period. Recurrent chlamydial infections in women have been associated with increased risks for PID and ectopic pregnancies.

Pregnant women: Few previous studies described risk factors for chlamydial infection in pregnant women, and these tended to be small and descriptive. Nonculture-testing techniques appear to perform well in pregnant populations, although studies are limited. A Cochrane review of 11 trials of interventions for treating genital chlamydia infection in pregnancy concluded that amoxicillin was as effective as erythromycin for achieving microbiological cure. The second Task Force recommendations for screening pregnant women were based on 2 studies in which improved pregnancy outcomes were demonstrated after patients were treated for chlamydial infection. We identified no recent studies on this topic in our literature search.

Men: Studies of prevalence rates and risk factors for chlamydial infection in men are limited. Being younger than 25 years of age is the strongest known risk factor cited so far. Results of swab specimens compared with first void urine specimens were similar for DNA amplification tests. DNA amplification techniques offer improved sensitivity and are more readily available than culture. The results of clinical trials indicated that azithromycin and doxycycline are equally efficacious, and both are more efficacious than erythromycin. Despite better compliance with single-dose treatment with azithromycin than multiple-dose treatment with doxycycline, cure rates are similar. No studies described the effectiveness of screening or early treatment for men in reducing transmission to women or in preventing acute infections or complications in men.

Cost: We retrieved 8 cost-effectiveness or cost-benefit analyses that either compared universal versus selective screening or evaluated the efficiency of various screening tests in women. Screening programs for detecting and treating chlamydia in women may provide cost savings in populations with moderate to high prevalence of chlamydia infection. Selective screening is more cost-effective than universal screening under most assumptions. Universal screening may be cost effective in certain populations in which the prevalence of chlamydia is high or the sensitivity of the selective screening criteria is low. If current estimates of the accuracy of DNA amplification assays are reasonable, these tests may improve the cost effectiveness of chlamydia screening. The cost effectiveness of screening for pregnant women, by use of selective screening criteria and new tests, is uncertain.

Conclusions:

Evidence for the effectiveness of screening nonpregnant women at risk has improved since the last recommendations from the USPSTF. There is growing evidence for the high performance of the new DNA amplification tests in which either endocervical swabs in women, urethral swabs in men, or urine specimens from men and women are used. No studies were found that described the effectiveness of screening or early treatment for men in reducing transmission to women or in preventing acute infections or complications in men.

Keywords:

Chlamydia trachomatis - screening - risk factors - screening tests

Prepared for: Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services.1 Contract No. 290-97-0018, Task Order No. 2, Technical Support of the U.S. Preventive Services Task Force. Prepared by: Oregon Health Sciences University Evidence-based Practice Center.

Suggested citation:

Nelson HD, Saha S, Helfand M. Screening for chlamydial infection. Systematic Evidence Review No. 3 (Prepared by the Oregon Health Sciences University Evidence-based Practice Center under Contract No 290-97-0018). AHRQ Publication No. 01-S003. Rockville, MD: Agency for Healthcare Research and Quality. March 2001.

The authors of this report are responsible for its content. Statements in the report should not be construed as endorsement by the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services of a particular drug, device, test, treatment, or other clinical service.

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2101 East Jefferson Street, Rockville, MD 20852. www​.ahrq.gov

Bookshelf ID: NBK42604PMID: 20722126