Screening for Gonorrhea and Chlamydia: A Systematic Review for the U.S. Preventive Services Task Force

In 2005, on the basis of epidemiologic studies of screening and studies of the diagnostic accuracy of screening tests (13), the U.S. Preventive Services Task Force (USPSTF) recommended screening for gonorrhea in all sexually active or pregnant women at increased risk for infection (4). It recommended against routine screening in low-risk men and nonpregnant women and found insufficient evidence to recommend for or against routine screening in high-risk men and low-risk pregnant women. In 2007, on the basis of studies of the effectiveness of screening, harms, and diagnostic accuracy of screening tests (13), the USPSTF recommended screening for chlamydia in all sexually active or pregnant women younger than 25 years and in older, high-risk women (5). It recommended against routine screening in low-risk women, regardless of pregnancy status, and found insufficient evidence to recommend for or against screening in men. Gonorrhea and chlamydia are the 2 most commonly reported sexually transmitted infections (STIs) in the United States (6). In 2012, totals of 334826 cases of gonorrhea and 1422976 cases of chlamydia were reported to the Centers for Disease Control and Prevention (6). However, the true incidence of gonorrhea and chlamydia is difficult to estimate because most infections are undetected. In women, gonococcal and chlamydial infections are most often asymptomatic but can cause cervicitis and complications of pelvic inflammatory disease (PID), ectopic pregnancy, infertility, and chronic pelvic pain (6, 7). In men, these infections can cause urethritis and epididymitis (6, 8). Most men with gonococcal urethritis are symptomatic, prompting timely treatment that prevents serious complications (9). However, gonococcal infections at extragenital sites, including the pharynx and rectum, and genital chlamydial infections are typically asymptomatic. Gonorrhea and chlamydia can also facilitate HIV transmission in both men and women (6, 10, 11). Infection with either gonorrhea or chlamydia in pregnant women can lead to adverse neonatal outcomes, including preterm birth and transmission of infection to the newborn. Chlamydial infection also causes neonatal ophthalmia and pneumonia in infants. Age is a strong predictor of risk for both gonorrhea and chlamydia, and infection rates are greatest among persons aged 15 to 24 years (6). Although rates are greater for women than men (108.7 cases of gonorrhea per 100000 women vs. 105.8 per 100000 men; 643.3 cases of chlamydia per 100000 women vs. 262.6 per 100000 men), rates have increased more rapidly among men in recent years (6). Other risk factors include having new or multiple sex partners or a partner with an STI, inconsistent condom use, and history of previous or coexisting STIs (1, 2). These risk factors are often used to define persons at increased risk in screening recommendations. Rates differ among population subgroups, and black and Hispanic persons generally have greater rates of infections compared with white persons (6, 12). Men who have sex with men who were tested in STD Surveillance Network clinics in 2012 had median prevalence rates of 16.4% for gonorrhea and 12.0% for chlamydia (6). This systematic review is an update of previous reviews for the USPSTF (13). It focuses on new studies of the effectiveness and adverse effects of gonorrhea and chlamydia screening in asymptomatic men and women, including pregnant women and adolescents, as well as the diagnostic accuracy of screening tests. Methods Methods are further described in a technical report (13). We followed a standard protocol consistent with the Agency for Healthcare Research and Quality (AHRQ) methods for systematic reviews (14). On the basis of evidence gaps identified from previous reviews (13), the USPSTF and AHRQ determined the key questions for this update (15). The investigators created analytic frameworks incorporating the key questions and outlining the patient populations, interventions, outcomes, and potential adverse effects (Supplements 1 and 2). A work plan was externally reviewed and modified but was not registered. Supplement 1. Analytic framework and key questions for screening men and nonpregnant women, including adolescents. Supplement 2. Analytic framework and key questions for screening pregnant women. The target populations were asymptomatic, sexually active men and women, including pregnant women and adolescents. The key questions focused on the effectiveness of screening compared with not screening in preventing adverse health outcomes, effectiveness of different screening strategies, diagnostic accuracy of screening tests, and potential harms of screening. Screening strategies included selective screening of high-risk groups, sampling from various anatomical sites, cotesting for concurrent STIs (including HIV), and using different screening intervals, among others. Outcomes included reduction of complications of infection and transmission or acquisition of disease, including gonorrhea, chlamydia, and HIV. For pregnant women, outcomes also included reduction in maternal complications and adverse pregnancy and infant outcomes. Harms of screening included labeling, anxiety, false-positive and false-negative test results, and other consequences of testing. The efficacy and harms of antibiotic treatments were well-established and were not further evaluated. Data Sources and Searches We searched Ovid MEDLINE (1 January 2004 to 13 June 2014), the Cochrane Central Register of Controlled Trials (May 2014), the Cochrane Database of Systematic Reviews (May 2014), the Health Technology Assessment Database (May 2014), the Database of Abstracts of Reviews of Effects (May 2014), and ClinicalTrials.gov (May 2014) and reviewed reference lists for additional citations (13). Search terms are provided in Supplement 3. Supplement 3. MEDLINE Search Strategies Study Selection Abstracts were selected for full-text review if they included asymptomatic, sexually active men and women, including pregnant women and adolescents; were relevant to a key question; and met additional prespecified inclusion criteria for each key question (13). Although this update was intended to evaluate studies published since the previous USPSTF reviews, the scope, key questions, and inclusion criteria differ across reviews, resulting in the inclusion of older studies that have not been previously reviewed. We included only English-language articles and excluded studies that were published as abstracts only or did not report original data. The selection of studies is summarized in a literature flow diagram Supplement 4. Two reviewers independently evaluated each study to determine inclusion eligibility. Supplement 4. Literature flow diagram. Only randomized, controlled trials (RCTs) and controlled observational studies were included to evaluate the effectiveness of screening, whereas uncontrolled observational studies were also included to determine adverse effects. Studies of screening strategies were included if they adequately described the study population and comparison groups, features of the screening program, and outcome measures. Inclusion criteria were less restrictive for effectiveness studies than diagnostic accuracy studies because the main comparison concerned outcomes related to the overall approach of screening compared with nonscreening rather than the characteristics of the individual tests. Studies of the accuracy of diagnostic tests were included if they evaluated screening tests in asymptomatic participants using technologies and methods that have been cleared by the U.S. Food and Drug Administration (FDA) and are available for clinical practice in the United States. These inclusion criteria reflect the scope of the USPSTF recommendations about technologies and medications. On the basis of these criteria, rectal, pharyngeal, and self-collected vaginal specimens obtained in nonclinical settings and point-of-care or in-house tests were excluded. Tests that were previously cleared and subsequently removed from the U.S. market (such as the ligase chain reaction test) were also excluded (16). Included studies used credible reference standards, adequately described the study population, defined positive test results, and reported performance characteristics of tests (such as sensitivity and specificity) or provided data to calculate them. Data Abstraction and Quality Rating A single investigator abstracted details about study design, patient population, comparison groups, setting, screening method, analysis, follow-up, and results. A second investigator reviewed data abstraction for accuracy. By using prespecified criteria for RCTs, cohort, and diagnostic accuracy studies developed by the USPSTF (14), 2 investigators independently rated the quality of studies (good, fair, or poor) and resolved discrepancies by consensus. Data Synthesis and Analysis Two independent reviewers assessed the internal validity (quality) of the body of evidence for the new studies for each key question using methods developed by the USPSTF, on the basis of the number, quality, and size of studies; consistency of results among studies; and directness of evidence (14, 15). Statistical meta-analysis was not done because of methodological limitations of the studies and heterogeneity in study designs, interventions, populations, and other factors. Studies included in previous reviews were reviewed for consistency with current results; however, lack of studies and differences in scope, key questions, and inclusion criteria limited aggregate synthesis with the updated evidence. Role of the Funding Source This research was funded by AHRQ under a contract to support the work of the USPSTF. The investigators worked with USPSTF members and AHRQ staff to develop and refine the scope, analytic frameworks, and key questions; resolve issues during the project; and finalize the report. AHRQ had no role in study selection, quality assessment, syn