title: Comparison of serological response to doxycycline versus benzathine penicillin G in the treatment of early syphilis in HIV-infected patients: a multi-center observational study.
abstract: BACKGROUND
  While doxycycline is recommended as an alternative treatment of syphilis in patients with penicillin allergy or intolerance, clinical studies to compare serological response to doxycycline versus benzathine penicillin in treatment of early syphilis among HIV-infected patients remain sparse.
  
  
  METHODS
  We retrospectively reviewed the medical records of HIV-infected patients with early syphilis who received doxycycline 100 mg twice daily for 14 days (doxycycline group) and those who received 1 dose of benzathine penicillin (2.4 million units) (penicillin group) between 2007 and 2013. Serological responses defined as a decline of rapid plasma reagin titer by 4-fold or greater at 6 and 12 months of treatment were compared between the two groups.
  
  
  RESULTS
  During the study period, 123 and 271 patients in the doxycycline and penicillin group, respectively, completed 6 months or longer follow-up. Ninety-one and 271 patients in the doxycycline and penicillin group, respectively, completed 12 months or longer follow-up. Clinical characteristics were similar between the two groups, except that, compared with penicillin group, doxycycline group had a lower proportion of patients with secondary syphilis (65.4% versus 41.5%, P<0.0001) and a higher proportion of patients with early latent syphilis (25.3% versus 49.6%, P<0.0001). No statistically significant differences were found in the serological response rates to doxycycline versus benzathine penicillin at 6 months (63.4% versus 72.3%, P = 0.075) and 12 months of treatment (65.9% versus 68.3%, P = 0.681). In multivariate analysis, secondary syphilis, but not treatment regimen, was consistently associated with serological response at 6 and 12 months of follow-up.
  
  
  CONCLUSIONS
  The serological response rates to a 14-day course of doxycycline and a single dose of benzathine penicillin were similar in HIV-infected patients with early syphilis at 6 and 12 months of follow-up. Patients with secondary syphilis were more likely to achieve serological response than those with other stages.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Department of Internal Medicine, Tzu-Chi Hospital and Tzu-Chi University College of Medicine, Hua-Lien, Taiwan.
authors.forename: Jen-Chih
authors.initials: JC
authors.lastname: Tsai
authors.affiliation: Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Yu-Huei
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital and College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Po-Liang
authors.initials: PL
authors.lastname: Lu
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan.
authors.forename: Ni-Jiin
authors.initials: NJ
authors.lastname: Shen
authors.affiliation: Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Chia-Jui
authors.initials: CJ
authors.lastname: Yang
authors.affiliation: Department of Internal Medicine, National Cheng Kung University College of Medicine and Hospital, Tainan, Taiwan.
authors.forename: Nan-Yao
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Hung-Jen
authors.initials: HJ
authors.lastname: Tang
authors.affiliation: Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Yuag-Meng
authors.initials: YM
authors.lastname: Liu
authors.affiliation: Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Wen-Chi
authors.initials: WC
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Chen-Hsiang
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, National Cheng Kung University College of Medicine and Hospital, Tainan, Taiwan.
authors.forename: Wen-Chien
authors.initials: WC
authors.lastname: Ko
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital and College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yen-Hsu
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan.
authors.forename: Hsi-Hsun
authors.initials: HH
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital and College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Internal Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Tun-Chieh
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; China Medical University, Taichung, Taiwan.
authors.forename: Chien-Ching
authors.initials: CC
authors.lastname: Hung
mesh_terms: D000328:Adult; D004318:Doxycycline / Q000627:therapeutic use*; D005500:Follow-Up Studies; D015658:HIV Infections / Q000150:complications* / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010401:Penicillin G Benzathine / Q000627:therapeutic use*; D013587:Syphilis / Q000097:blood / Q000150:complications* / Q000188:drug therapy*; D013588:Syphilis Serodiagnosis; D055815:Young Adult
chemical_list: D004318:Doxycycline; D010401:Penicillin G Benzathine