title: Prediction of Chlamydia trachomatis infection to facilitate selective screening on population and individual level: a cross-sectional study of a population-based screening programme.
abstract: To develop prediction models for Chlamydia trachomatis (Ct) infection with different levels of detail in information, that is, from readily available data in registries and from additional questionnaires.
  
  
  
  All inhabitants of Rotterdam and Amsterdam aged 16-29 were invited yearly from 2008 until 2011 for home-based testing. Their registry data included gender, age, ethnicity and neighbourhood-level socioeconomic status (SES). Participants were asked to fill in a questionnaire on education, sexually transmitted infection history, symptoms, partner information and sexual behaviour. We developed prediction models for Ct infection using first-time participant data-including registry variables only and with additional questionnaire variables-by multilevel logistic regression analysis to account for clustering within neighbourhoods. We assessed the discriminative ability by the area under the receiver operating characteristic curve (AUC).
  
  
  
  Four per cent (3540/80 385) of the participants was infected. The strongest registry predictors for Ct infection were young age (especially for women) and Surinamese, Antillean or sub-Saharan African ethnicity. Neighbourhood-level SES was of minor importance. Strong questionnaire predictors were low to intermediate education level, ethnicity of the partner (non-Dutch) and having sex with casual partners. When using a prediction model including questionnaire risk factors (AUC 0.74, 95% CI 0.736 to 0.752) for selective screening, 48% of the participating population needed to be screened to find 80% (95% CI 78.4% to 81.0%) of Ct infections. The model with registry risk factors only (AUC 0.67, 95% CI 0.656 to 0.675) required 60% to be screened to find 78% (95% CI 76.6% to 79.4%) of Ct infections.
  
  
  
  A registry-based prediction model can facilitate selective Ct screening at population level, with further refinement at the individual level by including questionnaire risk factors.
authors: Department of Public Health, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors: David
authors: D
authors: van Klaveren
authors: Department of Public Health, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Infectious Disease Control, Municipal Public Health Service Rotterdam-Rijnmond, Rotterdam, The Netherlands.
authors: Hannelore M
authors: HM
authors: Götz
authors: Epidemiology and Surveillance Unit, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors: Eline Lm
authors: EL
authors: Op de Coul
authors: Department of Public Health, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors: Ewout W
authors: EW
authors: Steyerberg
authors: Department of Public Health, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors: Yvonne
authors: Y
authors: Vergouwe
mesh_terms: D000293:Adolescent; D000328:Adult; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D002947:Cities; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000458:organization & administration*; D009426:Netherlands / Q000453:epidemiology; D012042:Registries / Q000706:statistics & numerical data*; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data; D012747:Sexual Partners / Q000523:psychology; D012923:Social Class; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: CHLAMYDIA TRACHOMATIS; INFECTION; PREVENTION; PUBLIC HEALTH; SCREENING