Recommendation Statement
This statement is an update of the 2001 U.S. Preventive Services Task Force
(USPSTF) recommendations about screening sexually active adolescents
and adults for chlamydial infection.
The USPSTF weighed the benefits (improved fertility,
pregnancy outcomes, and infection transmission) and harms (anxiety,
relationship problems, and unnecessary treatment of false positives)
of chlamydial screening identified in its 2001 recommendations
and the accompanying systematic review of English-language
articles published between July 2000 and July 2005.
Select for copyright and source information.
Contents
Summary of Recommendation
Clinical Considerations
Other Considerations
Discussion
Recommendations of Others
References
Members of the USPSTF
The U.S. Preventive Services Task Force (USPSTF)
makes recommendations about preventive care services for
patients without recognized signs or symptoms of the target
condition.
The USPSTF bases its recommendations on a systematic
review of the evidence of the benefits and harms and
an assessment of the net benefit of the service.
The USPSTF recognizes that clinical or policy decisions
involve more considerations than this body of evidence
alone. Clinicians and policymakers should understand
the evidence but individualize decision making to the
specific patient or situation.
Summary of Recommendation and Evidence
- 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 (Figure). 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 (Figure). 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 (Figure). 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 (Figure). This is a grade I Statement.
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Go to the section Clinical Considerations for discussion
of assessing risk for chlamydial infection in women and
suggestions for practice regarding screening for men.
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:
- Screening identifies infection in asymptomatic pregnant women.
- There is a relatively high prevalence of infection among pregnant women who are at increased risk.
- 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. This is a grade A Recommendation.
- For pregnant women at increased risk, the certainty is moderate that the benefits substantially outweigh the harms of screening for chlamydial infection. This is a grade 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. This is a grade 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. This is a grade I Statement.
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Clinical Considerations
Patient Population under Consideration
These recommendations target all sexually active individuals,
including adolescents and pregnant women.
Assessment of Risk
All sexually active women 24 years of age or younger,
including adolescents, are at increased risk for chlamydial
infection. In addition to sexual activity and age, other risk
factors for chlamydial infection include a history of chlamydial
or other sexually transmitted infection, new or multiple
sexual partners, inconsistent condom use, and exchanging
sex for money or drugs. Risk factors for pregnant
women are the same as for nonpregnant women.
Prevalence
of chlamydial infection varies widely among patient
populations. African-American and Hispanic women have
a higher prevalence of infection than the general population
in many communities and settings. Among men and
women, increased prevalence rates are also found in incarcerated
populations, military recruits, and patients at public
sexually transmitted infection clinics.
Screening Tests
Nucleic acid amplification tests have high specificity
and sensitivity when used as screening tests for chlamydial
infection. Nucleic acid amplification tests can be used with
urine and vaginal swabs, enabling screening when a pelvic
examination is not performed.
Treatment
Appropriate treatment of chlamydial infection has
been outlined by the Centers for Disease Control and Prevention
(CDC) (http://www.cdc.gov/std/treatment/). In its 2006
sexually transmitted disease treatment guidelines, the CDC
recommends that chlamydia infection be treated with 1 g
of azithromycin in a single oral dose or with oral doxycycline,
100 mg twice daily for 7 days. Pregnant women with
chlamydial infection may be treated with 1 g of azithromycin
in a single oral dose or amoxicillin, 500 mg orally 3
times daily for 7 days.1 Because the CDC updates these
recommendations regularly, clinicians are encouraged to
access the CDC Web site (http://www.cdc.gov/std/treatment/)
to obtain the most up-to-date information.
To prevent recurrent transmission, clinicians should
ensure that all sexual partners of infected individuals are
tested and treated if infected, or treated presumptively.
Screening Intervals
Screening for pregnant women who are at increased
risk for chlamydial infection is recommended at the first
prenatal visit. For pregnant women who remain at increased
risk and for those who acquire a new risk factor,
such as a new sexual partner, a screening should be conducted
during the third trimester. The optimal interval for
screening for nonpregnant women is unknown. The CDC
recommends at least annual screening for women at increased
risk.1
Suggestions for Practice in the Face of Insufficient
Evidence on Screening in Men
The USPSTF concluded that the evidence is insufficient
to determine the balance of benefits and harms related
to screening men for chlamydial infection. Specifically,
the USPSTF did not find evidence that screening
programs that target men result in a decreased incidence of
infection in women.
The USPSTF notes that programs
that screen men as a means of reducing transmission to
women are not common practice, that primary care clinicians
can institute screening in men, that the costs of additional
screening tests per individual are relatively low,
and that the potential harms of screening are small.
The
USPSTF recognizes that asymptomatic, untreated infections
in men provide a reservoir of infection that may make
it difficult to improve health outcomes in women through
screening programs that target only women. However,
given the low national rates of screening in women at risk,
the USPSTF believes that clinicians and health care systems
should focus on improving the screening rates among
women at increased risk, a group in which the benefits of
screening are certain.
Other Approaches to Prevention
Primary care clinicians and the health care systems in
which they work are responsible for ensuring that asymptomatic
women at risk for chlamydial infection are
screened. In some communities, this may involve home- or
school-based screening programs.
Useful Resources
See other USPSTF recommendations on screening for
sexually transmitted infections (hepatitis B and C virus
infection, HIV, genital herpes simplex, gonorrhea and
syphilis) at http://www.preventiveservices.ahrq.gov/.
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Other Considerations
Health Care System Needs
Screening rates for chlamydial infection among young
women in the United States remain very low. Public health
organizations, health care systems, and clinicians must
work together to develop and implement effective programs
to ensure that all women at increased risk are
screened for chlamydial infection.
Research Needs
There is a critical gap in the evidence relating to
whether chlamydia screening programs that target men decrease
the incidence of infection among women. Additional
research is also needed to determine the most effective
intervals for screening nonpregnant women, including
the potential for different followup intervals for women
with positive or negative test results. Continued research is
also needed on the potential harms of screening.
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Discussion
Burden of Disease
Chlamydia trachomatis infection is the most commonly
reported sexually transmitted infection in the United
States. In women, chlamydial infections commonly result
in cervicitis and urethritis. Untreated cases of C. trachomatis
infection in women frequently progress to PID. Pelvic
inflammatory disease, in turn, can lead to ectopic pregnancy,
infertility, and chronic pelvic pain. Chlamydial infection
during pregnancy is associated with adverse outcomes,
including miscarriage, premature rupture of
membranes, preterm labor, low birth weight, infant mortality,
neonatal chlamydial infection, and postpartum endometritis.
Chlamydial infection in men can cause nongonococcal
urethritis and acute epididymitis, and in rare
instances may result in urethral strictures and the Reiter
syndrome. In both men and women, chlamydial infection
is usually asymptomatic and, as with other inflammatory
sexually transmitted infection, chlamydial infection facilitates
the transmission of HIV infection among both men
and women in both the HIV carrier and recipient.2
In 2004, 929,462 chlamydial infections were reported
to the CDC. Unlike gonorrhea, the number of cases of
chlamydial infection reported to the CDC has increased
steadily over the past 10 years. This increase is thought to
be due to a combination of increased screening, more sensitive
screening tests, and increased emphasis on reporting
rather than an increasing incidence of infection. Since
2000, all 50 U.S. states and the District of Columbia have
instituted regulations requiring that cases of chlamydial infection be reported to the CDC. Because many cases continue
to remain undetected and unreported, the actual
number of new cases of chlamydial infection is thought to
be more than 2.8 million per year.2
Sexually active young women are at highest risk for
chlamydial infection. Women age 24 years or younger are
more than 5 times as likely as women older than age 30
years to be infected. Although chlamydial infection is
widely distributed among all racial and ethnic groups in the
United States, higher prevalence rates are found in African-American and Hispanic persons. Other risk factors include
a history of chlamydial infection or other sexually transmitted
infections, new or multiple sexual partners, inconsistent
condom use, and sex work. Risk factors for pregnant
women are the same as those for nonpregnant women.2
Scope of Review
In 2005, to update its 2001 recommendation on
screening for chlamydial infection, the USPSTF reviewed
the literature published on this topic between July 2000
and July 2005. The review focused on a systematic search
for direct evidence of the effect of screening in asymptomatic
individuals on health outcomes.
Assessment of Evidence
The 2001 USPSTF recommendation supporting
screening of women at increased risk for chlamydial infection
was based largely on the results of a good-quality randomized,
controlled trial of screening in a managed care
organization. This trial found that screening and treatment
of young women at risk for chlamydial infection reduced
the incidence of PID at 1 year of followup.3 In its
update, the USPSTF found only 1 study addressing the
effectiveness of screening for chlamydial infection among
nonpregnant women at increased risk. In a cluster randomized
trial, Østergaard and colleagues4 found that a
1-time home-based screening intervention was associated
with a lower prevalence of chlamydial infection and fewer
reported cases of PID at 1 year of followup. This study
was rated as being of poor quality because of significant
loss to followup; nonetheless, its findings were in line with
those of the earlier study. In its earlier review and in 2005,
the USPSTF did not find any studies evaluating health
outcomes related to screening programs in nonpregnant
women not at increased risk for infection, pregnant
women, or men.
The USPSTF considered each link in the evidence
chain for a screening service to make its recommendation and the accompanying
papers in this issue.5,6 These included the accuracy
of screening tests, the effectiveness of treatment,
estimation of the potential magnitude of benefit from
screening, and bounding of the potential for harms of
screening and treatment. (The term bounding comprises
the severity of the harm, the prevalence of the harm, and
how precise the data are on which estimates from it are
based.)
The USPSTF recommends screening for chlamydial
infection in all sexually active nonpregnant young women
age 24 years or younger. This represents a change in age
from the previous USPSTF recommendation on chlamydia
screening. This was done to align the recommendation
with the evidence in support of screening, including national
surveillance data assembled by the CDC.
Accuracy of Screening Tests
In 2001, the USPSTF conducted a systematic review
of the evidence related to screening technologies and concluded
that the body of evidence was fair. The USPSTF
noted at that time that many studies were performed under
optimal conditions and that most studies did not include
large screening populations with low prevalence rates.
While noting that NAATs had higher sensitivities and
specificities than older antigen detection tests and better
sensitivities than culture, the USPSTF did not offer any
specific clinical guidance as to what type of testing should
be used.
In 2002, the CDC published recommendations
concluding that NAATs be used when screening for chlamydial
infection in both women and men.7 Cook and
colleagues8 performed a systematic review of noninvasive
testing for chlamydial infection in 2005 and concluded
that urine-based screening using NAATs had comparable
sensitivity and specificity to cervical and urethral specimens.
Effectiveness of Treatment
The USPSTF recognizes the clinical benefits of treatment
of chlamydial infection in women with recognized
infection and therefore did not perform a systematic review
of the evidence of treatment. In 2001, the USPSTF
found fair evidence that treatment of chlamydial infection
during pregnancy improves pregnancy outcomes.7 The
USPSTF assessed the potential benefit of treating women
with chlamydial infection as substantial.
Harms
The USPSTF found no direct evidence of the harms
of chlamydia screening programs. Several small qualitative
studies, however, describe how women in whom chlamydial
infection is diagnosed (including women who did not
receive a diagnosis as part of screening programs) experience
anxiety and have significant concerns about their relationships
with male partners. The CDC recently commissioned
a study of the harms of screening for sexually
transmitted infections, including the harms associated with
a false-positive diagnosis. The harms associated with treatment
of chlamydial infection are mild to moderate gastrointestinal
symptoms, including nausea, diarrhea, and abdominal
pain.9 The USPSTF bounded the harms of
screening and treatment in men, women, and pregnant
women as small.
Estimate of Magnitude of Net Benefit
In considering the potential magnitude of benefit from
a screening program for chlamydial infection among
women, the USPSTF noted the documented effectiveness
of programs that screen nonpregnant women at increased
risk and concluded with high certainty that the benefits are
substantial. The USPSTF also concluded with moderate
certainty that the benefits of screening among pregnant
women at increased risk are substantial. Given the substantial
benefits and small harms, the USPSTF recommends
screening for chlamydial infection in all women at increased
risk, including pregnant women.
Women not at increased risk who are found to have
chlamydial infection through screening programs are likely
to benefit from treatment. Nevertheless, the USPSTF concluded
with moderate certainty that given the low prevalence
of infection among such women, the overall benefits
are likely to be small. Balancing the small benefits and
small harms, the USPSTF does not recommend routine
screening for chlamydial infection in women not at increased
risk for infection, including pregnant women not
at increased risk.
Although the direct benefits to men from screening
and treatment are relatively small, if benefits are found
among women resulting from screening in men, the potential
benefits to society are very large. In considering the
magnitude of benefit in screening men for chlamydial infection,
the USPSTF identified a significant evidence gap.
It is not known whether screening programs for men improve
health outcomes in women. Therefore, the USPSTF
found insufficient evidence to make a recommendation regarding
screening for chlamydia infection in men.
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Recommendations of Others
The American Academy of Family Physicians (AAFP),
American College of Obstetricians and Gynecologists
(ACOG), American College of Preventive Medicine
(ACPM), Canadian Task Force on Preventive Health, and
CDC all recommend screening for chlamydia in women at
increased risk for chlamydial infection. The ACPM and
Canadian Task Force recommend screening all pregnant
women, whereas the AAFP and ACOG recommend
screening pregnant women who are at increased risk for
chlamydial infection. The CDC also recommends at least
annual screening for chlamydia in men who have sex with
men.
The Web sites of these organizations provide further
information:
- American Academy of Family Physicians (2001): http://www.aafp.org/PreBuilt/RCPS_August2005.pdf
- American College of Obstetricians and Gynecologists (2002 and 2003): http://www.acog.org/publications/guidelinesForPerinatalCare/; http://www.acog.org/publications/committee_opinions/co292.cfm
- American College of Preventive Medicine Practice Policy Statement (2003): http://www.acpm.org/chlamydia.pdf
- Canadian Task Force on Preventive Health Care (1996): http://www.ctfphc.org/
- The Centers for Disease Control and Prevention (2006): http://www.cdc.gov/std/treatment/
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References
1. Centers for Disease Control and Prevention. Sexually transmitted diseases
treatment guidelines, 2006. MMWR Recomm Rep 2006;55:1-94. [PMID:
16888612]
2. Meyers DS, Halvorson H, Luckhaupt S. Screening for chlamydial infection:
an evidence update for the U.S. Preventive Services Task Force. Ann Intern Med
2007;147:000-000.
3. Scholes D, Stergachis A, Heidrich FE, Andrilla H, Holmes KK, Stamm WE.
Prevention of pelvic inflammatory disease by screening for cervical chlamydial
infection. N Engl J Med 1996;334:1362-6. [PMID: 8614421]
4. Ostergaard L, Andersen B, Møller JK, Olesen F. Home sampling versus
conventional swab sampling for screening of Chlamydia trachomatis in women: a
cluster-randomized 1-year follow-up study. Clin Infect Dis 2000;31:951-7.
[PMID: 11049776]
5. Guirguis-Blake J, Calonge N, Miller T, Siu A, Teutsch S, Whitlock E; U.S.
Preventive Services Task Force. Current processes of the U.S. Preventive Services
Task Force: refining evidence-based recommendation development. Ann Intern
Med 2007;147:117-22.
6. Barton MB, Miller T, Wolff T, Petitti D, LeFevre M, Sawaya G, et al.; U.S.
Preventive Services Task Force. How to read the new recommendation statement:
methods update from the U.S. Preventive Services Task Force. Ann Intern
Med 2007;147:123-7.
7. Johnson RE, Newhall WJ, Papp JR, Knapp JS, Black CM, Gift TL, et al.
Screening tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae infections—2002. MMWR Recomm Rep 2002;51:1-38; quiz CE1-4. [PMID:
12418541]
8. Cook RL, Hutchison SL, Østergaard L, Braithwaite RS, Ness RB. Systematic
review: noninvasive testing for Chlamydia trachomatis and Neisseria gonorrhoeae.
Ann Intern Med 2005;142:914-25. [PMID: 15941699]
9. Nelson HD, Helfand M. Screening for chlamydial infection. Am J Prev Med
2001;20:95-107. [PMID: 11306238]
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Members of the U.S. Preventive Services Task Force
Corresponding Author: Ned Calonge, M.D., M.P.H., Chair, U.S. Preventive Services Task Force, c/o Program Director, USPSTF, Agency for Healthcare Research and Quality, 540 Gaither Road, Rockville, MD 20850.
Members of the U.S. Preventive Services Task Force*:
Ned Calonge, M.D., M.P.H., Chair, USPSTF (Chief Medical Officer
and State Epidemiologist, Colorado Department of Public
Health and Environment, Denver, Colorado); Diana B. Petitti,
M.D., M.P.H. , Vice-chair, USPSTF (Senior Scientific Advisor for
Health Policy and Medicine, Regional Administration, Kaiser
Permanente Southern California, Pasadena, California); Thomas
G. DeWitt, M.D. (Carl Weihl Professor of Pediatrics and Director
of the Division of General and Community Pediatrics, Department
of Pediatrics, Children's Hospital Medical Center, Cincinnati,
Ohio); Leon Gordis, M.D., M.P.H., Dr.P.H. (Professor, Epidemiology
Department, Johns Hopkins Bloomberg School of
Public Health, Baltimore, Maryland); Kimberly D. Gregory,
M.D., M.P.H. (Director, Women's Health Services Research and
Maternal-Fetal Medicine, Department of Obstetrics and Gynecology,
Cedars-Sinai Medical Center, Los Angeles, California);
Russell Harris, M.D., M.P.H. (Professor of Medicine, Sheps Center
for Health Services Research, University of North Carolina
School of Medicine, Chapel Hill, North Carolina); Kenneth W.
Kizer, M.D., M.P.H. (President and CEO, National Quality Forum,
Washington, D.C.); Michael L. LeFevre, M.D., M.S.P.H.
(Professor, Department of Family and Community Medicine,
University of Missouri School of Medicine, Columbia, Missouri);
Carol Loveland-Cherry, Ph.D., R.N. (Executive Associate Dean,
Office of Academic Affairs, University of Michigan School of
Nursing, Ann Arbor, Michigan); Lucy N. Marion, Ph.D., R.N.
(Dean and Professor, School of Nursing, Medical College of
Georgia, Augusta, Georgia); Virginia A. Moyer, M.D., M.P.H.
(Professor, Department of Pediatrics, University of Texas Health
Science Center, Houston, Texas); Judith K. Ockene, Ph.D. (Professor
of Medicine and Chief of Division of Preventive and Behavioral
Medicine, University of Massachusetts Medical School,
Worcester, Massachusetts); George F. Sawaya, M.D. (Associate
Professor, Department of Obstetrics, Gynecology, and Reproductive
Sciences and Department of Epidemiology and Biostatistics,
University of California, San Francisco, California); Albert
L. Siu, M.D., M.S.P.H. (Professor and Chairman, Brookdale Department
of Geriatrics and Adult Development, Mount Sinai
Medical Center, New York, New York); Steven M. Teutsch,
M.D., M.P.H. (Executive Director, Outcomes Research and Management,
Merck & Company, Inc., West Point, Pennsylvania);
and Barbara P. Yawn, M.D., M.Sc. (Director of Research, Olmstead
Research Center, Rochester, Minnesota).
*Members of the Task Force at the time this recommendation was finalized. For a list of current Task Force members, go to http://www.ahrq.gov/clinic/uspstfab.htm.
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Copyright and Source Information
This document is in the public domain within the United States. For
information on reprinting, contact Randie Siegel, Director, Division of
Printing and Electronic Publishing, Agency for Healthcare Research and Quality,
540 Gaither Road, Rockville, MD 20850.
Requests for linking or to incorporate content in electronic resources
should be sent to: info@ahrq.gov.
Source: U.S. Preventive Services Task Force. Screening for chlamydial infection: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med 2007;147:128-33.
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Current as of June 2007
Internet Citation:
U.S. Preventive Services Task Force. Screening for Chlamydial Infection: U.S. Preventive Services Task Force Recommendation Statement. June 2007. First published in Ann Intern Med 2007;147:128-33. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/uspstf07/chlamydia/chlamydiars.htm