Screening for Chlamydial Infection

• The U.S. Preventive Services Task Force (USPSTF) recommends screening for chlamydial infection for all sexually active non-pregnant young women aged 24 and younger and for older non-pregnant women who are at increased risk . This is a grade "A" Recommendation.
• The USPSTF recommends screening for chlamydial infection for all pregnant women aged 24 and younger and for older pregnant women who are at increased risk . This is a grade "B" Recommendation.
• The USPSTF recommends against routinely providing screening for chlamydial infection for women aged 25 and older, whether or not they are pregnant, if they are not at increased risk . This is a grade "C" Recommendation.
• The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydial infection for men . This is a grade "I" Statement.

Rationale:

Importance: Chlamydial infection is the most common sexually transmitted bacterial infection in the United States. In women, genital chlamydial infection may result in urethritis, cervicitis, pelvic inflammatory disease (PID), infertility, ectopic pregnancy, and chronic pelvic pain. Chlamydial infection during pregnancy is related to adverse pregnancy outcomes, including miscarriage, premature rupture of membranes, preterm labor, low birth weight, and infant mortality.

Detection:The USPSTF found fair evidence that nucleic acid amplification tests (NAATs) can identify chlamydial infection in asymptomatic men and women, including asymptomatic pregnant women, with high test specificity. In low prevalence populations, however, a positive test is more likely to be a false positive than a true positive, even with the most accurate tests available.

Benefits of detection and early intervention:

• Non-pregnant women at increased risk. There is good evidence that screening for chlamydial infection in women who are at increased risk can reduce the incidence of PID. The USPSTF concluded that the benefits of screening women at increased risk are substantial.
• Pregnant women at increased risk. There are no studies evaluating the effectiveness of screening for chlamydial infection in pregnant women who are at increased risk. The USPSTF, however, found the following:
  1. There is fair evidence that screening identifies infection in asymptomatic pregnant women.
  2. There is a relatively high prevalence of infection among pregnant women who are at increased risk.
  3. There is fair evidence of improved pregnancy and birth outcomes for women who are treated for chlamydial infection.
  The USPSTF concluded that the benefits of screening pregnant women who are at increased risk are substantial.
• Women not at increased risk. The USPSTF identified no studies documenting the benefits of screening women, including pregnant women, who are not at increased risk for chlamydial infection. While recognizing the potential benefit to women identified through screening, the USPSTF concluded the overall benefit of screening would be small, given the low prevalence of infection among women not at increased risk.
• Men. While concluding that the direct benefit to men of screening was likely to be small, the USPSTF noted that screening for chlamydial infection in men may be beneficial if it were to lead to a decreased incidence of chlamydial infection in women. The USPSTF did not, however, find evidence to support this outcome, and therefore concluded that the benefits of screening men are unknown. The USPSTF identified this as a critical gap in the evidence.

Harms of detection and early treatment: The USPSTF concluded that the harms of screening for chlamydial infection are no greater than small, although few studies have been published on this subject. Potential harms include anxiety and relationship problems arising from false positive results and over-treatment.

The USPSTF identified the lack of evidence related to potential harms of screening as a gap in the evidence.

The USPSTF reached the following conclusions:

• For non-pregnant women at increased risk, the certainty is high that the benefits of screening for chlamydial infection substantially outweigh the harms. ("A" Recommendation)
• For pregnant women at increased risk, the certainty is moderate that the benefits substantially outweigh the harms of screening for chlamydial infection. ("B" Recommendation)
• For women not at increased risk (including pregnant women not at increased risk), the certainty is moderate that the benefits outweigh the harms of screening to only a small degree. There may be considerations that support screening an individual patient. ("C" Recommendation)
• For men, the benefits of screening are not known; thus, the USPSTF could not determine the balance of benefits and harms of screening men for chlamydial infection. ("I" Statement)