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Table 1. Summary of EvidenceI,1-4

Key questions Evidence codesa Quality of evidenceb
Arrow 1
Does screening reduce adverse health outcomes?
Nonpregnant women I, II-3 Good: one randomized controlled trial indicates screening reduces pelvic inflammatory disease.
Pregnant women II-2, II-3 Fair: no new studies; 2 studies used in prior recommendations indicate improved birth outcomes when pregnant women are screened and treated, although the control group was based on temporal changes in treatment standards in one key study, differences between cases and controls were not different in another study.
Men III Poor: no studies of effectiveness of screening in preventing acute infections or complications.
Arrow 2
Does screening reduce the prevalence of infection? II-3 Poor-fair: uncontrolled studies based on time trends after initiation of screening, studies from many populations and settings report declining rates.
Are risk factors useful for selective screening?
Nonpregnant women II-2 Fair: few studies in low prevalence, community populations, studies agree on age.
Pregnant women III Poor: very few studies based on small populations, descriptive.
Men III Poor: subjects mainly from sexually transmitted disease clinics, jail, etc, descriptive.
What screening tests should be performed?
Nonpregnant women II-1 Fair: many studies about test performance under study conditions, not well tested in large screening populations with low prevalence.
Pregnant women II-1 Fair: few studies about test performance under study conditions, not tested in large screening populations.
Men II-1 Fair: many studies about test performance under study conditions, not well tested in large screening populations with low prevalence.
Arrow 3
What are the implications of recurrent infection?
Nonpregnant women II-2 Fair: studies include high-risk subjects, lack of internal control groups, report descriptive data.
[a] Study design categories (Guide to Clinical Preventive Services, 56).
[b] Quality of evidence ratings based on criteria developed by the third U.S. Preventive Services Task Force.
[I] I: Randomized, controlled trials.
[1] II-1: Controlled trials without randomization.
[2] II-2: Cohort or case-control analytic studies.
[3] II-3: Multiple time series, dramatic uncontrolled experiments.
[4] III: Opinions of respected authorities, descriptive epidemiology.

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