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Nelson HD, Zakher B, Cantor A, et al. Screening for Gonorrhea and Chlamydia: Systematic Review to Update the U.S. Preventive Services Task Force Recommendations [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2014 Sep. (Evidence Syntheses, No. 115.)

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Screening for Gonorrhea and Chlamydia: Systematic Review to Update the U.S. Preventive Services Task Force Recommendations [Internet].

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1INTRODUCTION

Purpose and Previous U.S. Preventive Services Task Force Recommendation

This report will be used by the U.S. Preventive Services Task Force (USPSTF) to update its 2005 recommendation on screening for gonorrhea1 and its 2007 recommendation on screening for chlamydia.2 It focuses on studies published since prior USPSTF systematic reviews of these topics.3-5 Appendix A provides a description of terms and abbreviations used in this report.

In 2005, the USPSTF issued a B recommendation to screen for gonorrhea in all sexually active women at increased risk for infection, including pregnant women.1 Women at increased risk include those who are younger than age 25 years; live in high prevalence communities; have a history of gonococcal infection or other sexually transmitted infections (STIs); have new or multiple sex partners; or engage in inconsistent condom use, sex work, or drug use. The USPSTF recommended against routine screening in men and nonpregnant women at low risk for infection (D recommendation), and found insufficient evidence to recommend for or against routine screening in high-risk men and low-risk pregnant women (I statement).

In 2007, the USPSTF issued an A recommendation to screen for chlamydia in all sexually active nonpregnant women younger than age 25 years and in older high-risk nonpregnant women (i.e., those who have a history of chlamydial infection or other STIs, have new or multiple sex partners, or engage in inconsistent condom use or sex work).2 The age specification for screening in the 2007 recommendation differed from the previous recommendation (age ≤25 years) in order to align with evidence on screening, including national surveillance data from the Centers for Disease Control and Prevention (CDC). The USPSTF also recommended screening in pregnant women younger than age 25 years and in older high-risk pregnant women (B recommendation), and recommended against routine screening in low-risk women age 25 years or older regardless of pregnancy status (C recommendation). The USPSTF found insufficient evidence to recommend for or against routine screening in men (I statement).

Condition Definition

Gonorrhea is an STI caused by the bacterium Neisseria gonorrhoeae, a gram-negative intracellular diplococcus that infects the mucosal epithelium of the genital tract.6,7 Other sites of infection include the conjunctiva, oropharynx, and rectum. Infection with N. gonorrhoeae often leads to local inflammation and, in women, can ascend the urogenital tract and cause pelvic inflammatory disease (PID).6 Infants born to infected mothers may contract gonococcal eye disease in the first few days of life.8

Chlamydia is an STI caused by the bacterium Chlamydia trachomatis. Most C. trachomatis strains infect the epithelial cells of the genital tract, causing inflammation that may be asymptomatic or present as erythema, edema, and mucopurulent discharge.9 Infections of the rectum can cause proctitis, while infections of the oropharynx are typically asymptomatic. Inflammation damages the epithelium and leads to scar formation. In women, scarring may ultimately lead to fallopian tube occlusion and infertility years after active infection. Infants born to infected mothers may contract chlamydial eye disease and pneumonia.8,9

Prevalence

Gonorrhea is the second most commonly reported STI in the United States after chlamydia. In 2012, 334,826 cases were reported to the CDC, although less than half of all cases are actually diagnosed and reported.10 Prevalence rates among women and men are similar (108.7 vs. 105.8 cases per 100,000, respectively), and the highest rates of infection are among persons ages 15 to 24 years.

Chlamydia is the most commonly reported STI in the United States. In 2012, 1,422,976 cases of chlamydia were reported to the CDC.10 However, the true incidence of chlamydia is difficult to accurately estimate because most infections are asymptomatic and are therefore undetected. In 2012, the rate of chlamydial infection among women (643.3 cases per 100,000) was more than double the rate among men (262.6 cases per 100,000), with the majority of cases occurring among women ages 15 to 24 years.

Estimates of coinfection with both gonorrhea and chlamydia are not available.

Pregnancy

In 2011, CDC surveillance data indicated that the median State-specific gonorrhea positivity rate among women ages 15 to 24 years screened in selected prenatal clinics in 15 states, Puerto Rico, and the Virgin Islands was 0.8 percent (range, 0.0% to 3.8%), and the chlamydia positivity rate was 7.7 percent (range, 2.8% to 16.3%).8 The risk for mother-to-child transmission of gonorrhea is between 30 and 47 percent.11

Etiology, Natural History, and Burden of Disease

Gonococcal infections in women are often asymptomatic, but can cause cervicitis and complications of PID, such as ectopic pregnancy, infertility, and chronic pelvic pain.8 Gonorrhea in men can lead to symptomatic urethritis, epididymitis, and prostatitis.12 The majority of urethral infections in men are symptomatic, resulting in timely treatment that prevents serious complications.13 However, infections at extragenital sites (i.e., pharynx and rectum) are typically asymptomatic. Rarely, local gonococcal infections disseminate, causing an acute dermatitis tenosynovitis syndrome that can be complicated by arthritis, meningitis, or endocarditis.7,14 Gonorrhea facilitates HIV transmission in both men and women.8

As with gonorrhea, chlamydial infections in women are usually asymptomatic, but can cause cervicitis and urethritis.15 Ten to 15 percent of untreated chlamydial infections progress to symptomatic PID that can cause infertility, chronic pelvic pain, and ectopic pregnancy.8,15 Genital chlamydial infection in men is usually asymptomatic, but can cause nongonococcal urethritis, epididymitis, and, in rare instances, uretheral strictures and reactive arthritis.8,16 Chlamydia can also infect nongenital sites and can facilitate the transmission of HIV infection.8,17,18

Risk Factors

Age is a strong predictor of risk for both gonorrhea and chlamydia. In 2012, rates of gonococcal infection reported to the CDC were highest among women ages 20 to 24 years (578.5 cases per 100,000), women ages 15 to 19 years (521.2 cases per 100,000), and men ages 20 to 24 years (462.8 cases per 100,000). Rates of chlamydial infection were also highest among women ages 20 to 24 years (3,695.5 cases per 100,000), women ages 15 to 19 years (3,291.5 cases per 100,000), and men ages 20 to 24 years (1,350.4 cases per 100,000).10

Infection rates vary by race and ethnicity. In 2012, rates of gonococcal infection among blacks (462.0 cases per 100,000), American Indians/Alaska Natives (124.9 cases per 100,000), Native Hawaiians/Other Pacific Islanders (87.8 cases per 100,000), and Hispanics (60.4 cases per 100,000) were higher than among whites (31.0 cases per 100,000) and Asians (16.9 cases per 100,000). The rates of chlamydial infection among blacks (1,229.4 cases per 100,000), American Indians/Alaska Natives (728.2 cases per 100,000), Native Hawaiians/Other Pacific Islanders (590.4 cases per 100,000), and Hispanics (380.3 cases per 100,000) were also higher than among whites (179.6 cases per 100,000) and Asians (112.9 cases per 100,000).10

Infection rates are high among specific population subgroups. Among men who have sex with men (MSM) tested at 42 STI clinics in 12 local and state health jurisdictions during 2012, the median gonorrhea prevalence rate was 16.4 percent (range, 9.8% to 30.4%), and the chlamydia prevalence rate was 12.0 percent (range, 6.4% to 22.2%).10 Among men and women enrolled in the National Job Training Program, a program for socioeconomically disadvantaged youth ages 16 to 24 years, median prevalence rates for chlamydia in 2012 were 11.0 percent (range, 5.5% to 19.4%) in women and 7.0 percent (range, 0.6% to 13.5%) in men.10 Prevalence rates for gonorrhea were 1.3 percent (range, 0.0% to 4.8%) in women and 0.7 percent (range, 0.0% to 2.8%) in men. Among adolescents entering selected juvenile correctional facilities in 2011, prevalence of gonorrhea ranged from 0.1 to 4.9 percent and from 5.4 to 17.3 percent for chlamydia.8 Prevalence rates were generally higher among women than men for both infections.

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.3,4

Rationale for Screening and Screening Strategies

Gonorrhea and chlamydia are often asymptomatic in infected women, but can cause serious complications10 and be transmitted to sex partners and unborn children. Screening has the potential to improve the detection and treatment of infected individuals and reduce the severity of complications of untreated disease and transmission. The two infections have comparable distributions in populations and can be detected using similar tests from the same specimen. The availability of accurate screening tests and effective treatments make screening a feasible approach.

Interventions and Treatment

Infection with N. gonorrhoeae can be detected by nucleic acid amplification tests (NAATs) using male and female urine and clinician-collected endocervical, vaginal, and male urethral specimens.10 Most NAATs cleared for use on clinician-collected vaginal swabs are also cleared for use on self-collected vaginal specimens obtained in clinical settings. Rectal and pharyngeal swabs can be collected from persons who engage in receptive anal and oral intercourse, although these sites of collection have not been cleared by the U.S. Food and Drug Administration (FDA). Gonorrhea can also be detected by culture, which is recommended for diagnosing resistant strains and for detecting strains with decreased antimicrobial susceptibility. Antimicrobial susceptibility testing can only be performed using culture.

Current recommendations support using NAATs to detect C. trachomatis infections because their sensitivity and specificity are high and they have been cleared by the FDA for use on urogenital sites, including male and female urine, as well as clinician-collected endocervical, vaginal, and male urethral specimens.10 Most NAATs cleared for use on vaginal swabs are also cleared for use on self-collected vaginal specimens obtained in clinical settings. Rectal swabs can be collected from persons who engage in receptive anal intercourse, although this site of collection has not been cleared by the FDA.

Gonorrhea and chlamydia respond to antibiotic treatment. In recent years, treatment of gonorrhea has been complicated by increasing drug resistance. For nonpregnant adults, new recommendations have replaced the use of oral cephalosporins with a single intramuscular dose of ceftriaxone in combination with either single-dose azithromycin or 7-day doxycycline for the treatment of uncomplicated gonorrhea of the cervix, urethra, and rectum.19 Combination therapy is recommended to prevent the development of further drug resistance, as well as to treat commonly coexisting chlamydia. Azithromycin is generally preferred to doxycycline as the secondary drug in gonorrhea combination treatment because of its convenience as a single-dose therapy, as well as evidence of gonorrhea resistance to tetracyclines such as doxycycline. Chlamydia is treated with single-dose azithromycin or 7-day doxycycline.13 In patients for whom adherence or followup is a concern, azithromycin is the preferred choice because it provides a single dose of directly observed treatment.

For patients with either gonorrhea or chlamydia, all sex partners from the preceding 60 days should be evaluated and treated for infection.13,15,19 Expedited partner therapy is a means of treatment in which medication or a prescription is delivered to the partner by the patient, a disease investigation specialist, or a pharmacy.19 In the case of treatment for gonorrhea, the partner would receive oral combination therapy with cefixime and azithromycin, rather than intramuscular ceftriaxone. All patients diagnosed with gonorrhea or chlamydia require retesting 3 months after treatment.13,15

Pregnancy

Pregnant women infected with gonorrhea require intramuscular ceftriaxone and oral azithromycin.10,13 Chlamydial infections in pregnant women are treated with single-dose azithromycin or 7-day amoxicillin.13 In addition, a test of cure to document eradication of chlamydial infection 3 weeks after treatment is recommended. Pregnant women diagnosed with chlamydia or gonorrhea in the first trimester should also be retested 3 months after treatment. Gonococcal neonatal ophthalmia, resulting from transmission from an untreated woman to her newborn, may be prevented with routine topical prophylaxis at delivery. However, prevention of chlamydial neonatal pneumonia and ophthalmia require prenatal detection and treatment.

Current Clinical Practice

Despite current guidelines that recommend screening for gonorrhea and chlamydia in high-risk persons, a review of the health care claims of 4,296 men and women presenting for general medical or gynecological examinations from 2000 to 2003 found that almost none had codes for screening for HIV, syphilis, gonorrhea, or chlamydia, regardless of their high-risk sexual behavior status.20 Among patients claiming high-risk sexual behaviors, only 21 to 56 percent were tested for gonorrhea and 21 to 60 percent were tested for chlamydia. Similarly, a review of the U.S. Healthcare Effectiveness Data and Information Set from 2000 to 2007 showed a 64.4 percent increase in testing for chlamydia among young, sexually active women enrolled in commercial and Medicaid health plans during that period; however, the testing rate in 2007 was only 41.6 percent.21 Population-based survey data from 2005 to 2008 in the United States indicated that many pregnant women were not tested, and followup testing was not always performed.22

Recommendations of Other Groups

The CDC's recommendations are similar to those of the USPSTF and include targeted screening for gonorrhea and chlamydia in women at increased risk, while screening in other groups, including men, is not recommended.1,2,13 The CDC also advises screening in other selected high-risk populations, including MSM and young women in juvenile detention or jail facilities. Recommendations from the CDC and other professional groups are summarized in Table 1.

Table 1. Recommendations of Other Groups.

Table 1

Recommendations of Other Groups.

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