title: Randomised controlled trial of screening for Chlamydia trachomatis to prevent pelvic inflammatory disease: the POPI (prevention of pelvic infection) trial.
abstract: OBJECTIVE
  To determine whether screening and treating women for chlamydial infection reduces the incidence of pelvic inflammatory disease over the subsequent 12 months.
  
  
  METHODS
  Randomised controlled trial.
  
  
  METHODS
  Common rooms, lecture theatres, and student bars at universities and further education colleges in London.
  
  
  METHODS
  2529 sexually active female students, mean age 21 years (range 16-27).
  
  
  METHODS
  Participants completed a questionnaire and provided self taken vaginal swabs, with follow-up after one year. Samples were randomly allocated to immediate testing and treatment for chlamydial infection, or storage and analysis after a year (deferred screening controls).
  
  
  METHODS
  Incidence of clinical pelvic inflammatory disease over 12 months.
  
  
  RESULTS
  Baseline prevalence of chlamydia was 5.4% (68/1254) in screened women and 5.9% (75/1265) in controls. 94% (2377/2529) of women were followed up after 12 months. The incidence of pelvic inflammatory disease was 1.3% (15/1191) in screened women compared with 1.9% (23/1186) in controls (relative risk 0.65, 95% confidence interval 0.34 to 1.22). Seven of 74 control women (9.5%, 95% confidence interval 4.7% to 18.3%) who tested positive for chlamydial infection at baseline developed pelvic inflammatory disease over 12 months compared with one of 63 (1.6%) screened women (relative risk 0.17, 0.03 to 1.01). However, most episodes of pelvic inflammatory disease occurred in women who tested negative for chlamydia at baseline (79%, 30/38). 22% (527/2377) of women reported being tested independently for chlamydia during the trial.
  
  
  CONCLUSIONS
  Although some evidence suggests that screening for chlamydia reduces rates of pelvic inflammatory disease, especially in women with chlamydial infection at baseline, the effectiveness of a single chlamydia test in preventing pelvic inflammatory disease over 12 months may have been overestimated. Trial registration ClinicalTrials.gov NCT00115388.
authors.affiliation: Division of Community Health Sciences, St George's, University of London SW17 0RE. oakeshot@sgul.ac.uk
authors.forename: Pippa
authors.initials: P
authors.lastname: Oakeshott
authors.forename: Sally
authors.initials: S
authors.lastname: Kerry
authors.forename: Adamma
authors.initials: A
authors.lastname: Aghaizu
authors.forename: Helen
authors.initials: H
authors.lastname: Atherton
authors.forename: Sima
authors.initials: S
authors.lastname: Hay
authors.forename: David
authors.initials: D
authors.lastname: Taylor-Robinson
authors.forename: Ian
authors.initials: I
authors.lastname: Simms
authors.forename: Phillip
authors.initials: P
authors.lastname: Hay
mesh_terms: D000293:Adolescent; D002690:Chlamydia Infections / Q000453:epidemiology / Q000517:prevention & control*; D002692:Chlamydia trachomatis; D005260:Female; D006801:Humans; D015994:Incidence; D008131:London / Q000453:epidemiology; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D000292:Pelvic Inflammatory Disease / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D012725:Sexual Behavior; D012747:Sexual Partners; D055815:Young Adult