title: Azithromycin Treatment Failure for Chlamydia trachomatis Among Heterosexual Men With Nongonococcal Urethritis.
abstract: Three recent prospective studies have suggested that the 1-g dose of azithromycin for Chlamydia trachomatis (Ct) was less effective than expected, reporting a wide range of treatment failure rates (5.8%-22.6%). Reasons for the disparate results could be attributed to geographic or methodological differences. The purpose of this study was to reexamine the studies and attempt to harmonize methodologies to reduce misclassification as a result of false positives from early test-of-cure (TOC) or reinfection as a result of sexual exposure rather than treatment failure.
  
  
  
  Men who had sex with women, who received 1-g azithromycin under directly observed therapy for presumptive treatment of nongonococcal urethritis with confirmed Ct were included. Baseline screening was performed on urethral swabs or urine, and TOC screening was performed on urine using nucleic acid amplification tests. Posttreatment vaginal sexual exposure was elicited at TOC. Data from the 3 studies were obtained and reanalyzed. Rates of Ct retest positive were examined for all cases, and a sensitivity analysis was conducted to either reclassify potential false positives/reinfections as negative or remove them from the analysis.
  
  
  
  The crude treatment failure rate was 12.8% (31/242). The rate when potential false positives/reinfections were reclassified as negative was 6.2% (15/242) or when these were excluded from analysis was 10.9% (15/138).
  
  
  
  In these samples of men who have sex with women with Ct-related nongonococcal urethritis, azithromycin treatment failure was between 6.2% and 12.8%. This range of failure is lower than previously published but higher than the desired World Health Organization's target chlamydia treatment failure rate of < 5%.
authors.affiliation: From the *Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA; †Department of Epidemiology, ‡Department of Global Health, University of Washington, Seattle, WA; §Department of Medicine, University of Alabama at Birmingham, Birmingham, AL; ∥Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA; and ¶Department of Medicine, University of Mississippi Medical Center, Jackson, MS.
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Kissinger
authors.forename: Scott
authors.initials: S
authors.lastname: White
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Manhart
authors.forename: Jane
authors.initials: J
authors.lastname: Schwebke
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Taylor
authors.forename: Leandro
authors.initials: L
authors.lastname: Mena
authors.forename: Christine M
authors.initials: CM
authors.lastname: Khosropour
authors.forename: Larissa
authors.initials: L
authors.lastname: Wilcox
authors.forename: Norine
authors.initials: N
authors.lastname: Schmidt
authors.forename: David H
authors.initials: DH
authors.lastname: Martin
mesh_terms: D017963:Azithromycin / Q000627:therapeutic use*; D002690:Chlamydia Infections / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D003951:Diagnostic Errors; D005189:False Positive Reactions; D020010:Heterosexuality; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D017211:Treatment Failure; D014526:Urethritis / Q000150:complications*
chemical_list: D017963:Azithromycin