title: Predictors of chlamydial infection and gonorrhea among patients seen by private practitioners.
abstract: OBJECTIVE
  To identify the predictors of chlamydial infection and gonorrhea among patients tested by general practitioners.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  General private practice, family planning and abortion clinic, adolescent clinic, sexually transmitted disease (STD) clinic and community health clinic in downtown Montreal.
  
  
  METHODS
  The 2856 patients were included because of symptoms compatible with an STD, a history of sexual contact with a person known or suspected to have chlamydial infection, a history of a nonexclusive sexual relationship or presentation for an abortion.
  
  
  METHODS
  Patient information was obtained by the attending physician on a standard form. Enzyme immunoassay (EIA) for Chlamydia trachomatis and culture for Neisseria gonorrhoeae were performed on cervical (female) or urethral (male) samples. Stepwise logistic regression was used to identify the predictors of infection.
  
  
  RESULTS
  The EIA results were positive in 11.1% of the cases and the culture results in 2.3%. Among the males chlamydial infection was independently associated with low age (odds ratio [OR] = 0.88 per year), heterosexuality (OR = 4.99), urethral discharge (OR = 3.74) and the absence of a history of gonorrhea (OR = 0.51). Gonorrhea was associated with urethral discharge (OR = 24.3) and homosexuality (OR = 3.68). Among the females chlamydial infection was associated with low age (OR = 0.79 per year), a history of sexual contact with a person known to have chlamydial infection (OR = 2.30), multiple sexual partners in the previous 12 months (OR = 1.60) and a reason for the test other than screening purposes (OR = 0.60). Gonorrhea was associated with a reason other than screening (OR = 0.24) and low age (OR = 0.74 per year). Among the patients tested for screening purposes age was the only significant predictor of chlamydial infection (OR = 0.79 per year), and the prevalence of gonorrhea was 0.4%. The actual rate of chlamydial infection was 11.8% among the patients younger than 25 years, 5.7% among those 25 to 34 years and 0.6% among those over 34.
  
  
  CONCLUSIONS
  Age alone can be used as a criterion to screen for chlamydial infection among asymptomatic patients without a history of sexual contact with a person known or suspected to have such infection and with a history of a nonexclusive relationship. The prevalence in our population justifies screening people up to 34 years of age.
authors.affiliation: Service de microbiologie et de maladies infectieuses, Hôpital Saint-Luc, Montréal.
authors.forename: J
authors.initials: J
authors.lastname: Vincelette
authors.forename: J G
authors.initials: JG
authors.lastname: Baril
authors.forename: R
authors.initials: R
authors.lastname: Allard
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008297:Male; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011792:Quebec; D012723:Sex; D012737:Sex Factors