Successful prevention of syphilis infection with azithromycin in both HIV-negative and HIV-positive individuals, San Francisco, 1999-2003.

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Successful prevention of syphilis infection with
azithromycin in both HIV-negative and
HIV-positive individuals, San Francisco,
1999-2003.

• J. D. Klausner,1,2 K. Steiner,1 R. Kohn11San
  Francisco Dept Public Health, San Francisco, CA
  2University of California, San Francisco, San
  Francisco, CA.

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Background Syphilis trends in San Francisco
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Background Current syphilis epidemic in San
Francisco
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BackgroundPrevious studies on azithromycin and
syphilis

• Hook EW, Stephens J, Ennis DM, Ann Intern Med,
  1999
• randomized trial of 1 gram azithromycin vs. 2.4
  mu benzathine penicillin for incubating disease
• no reactive FTA-ABS at 3 months in either group
• Hook EW et al., Sex Trans Dis, 2001
• RCT of azithromycin vs. benzathine penicillin for
  syphilis cases
• 2 grams of azithromycin as effective as
  benzathine penicillin for treating disease

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BackgroundSyphilis treatment in San Francisco

• Contacts new cases versus epi treatment
• 2.4 mu benzathine penicillin G I.M. (bicillin)
• 100 mg doxycycline P.O. BID for 14 days
• 1 gram azithromycin P.O.
• Field-delivered therapy with Azithromycin began
  March, 1999

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Objective

• Compare observed success in treating incubating
  syphilis using azithromycin to success with other
  treatments in order to justify continued use of
  azithromycin

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MethodsSan Francisco STD Registry

• STD clinic medical record data
• Reported morbidity and reactive STS
• Interview data and field activity
• Screening data

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Methods Sample

• Data from 1999 through 2003
• Non-reactive RPR or VDRL with any syphilis
  treatment (n3812)
• Follow-up titer between 30 and 90 days after
  initial titer (n151)

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Methods Measurements

• Outcome any reactive titer defines treatment
  failure
• Biological false positives excluded from analysis
• HIV status measured from multiple sources,
  including self-reported status

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ResultsAll patients
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Results By HIV Status
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Conclusions

• Failure rate for azithromycin was not
  significantly greater than rate for bicillin
• Since no resistance to bicillin has been
  documented, apparent treatment failures likely
  indicate re-exposure
• Success in treatment did not vary between
  HIV-negative and HIV-positive clients

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Limitations

• No way to distinguish treatment failure from
  re-exposure
• Not all exposed will develop disease
• No randomization
• penicillin allergies
• field versus clinic
• Small number of follow-up titers
• Wide confidence limits for negative results

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Limitations

• No power to assess temporal trends
• Azithromycin epi-treatment failures
• November 2002
• April 2003
• July 2003
• Bicillin epi-treatment failure
• April 1999

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Further research

• Another randomized trial of azithromycin vs.
  bicillin
• HIV-positive clients only
• San Francisco Los Angeles
• Five years later than 1999 study by Hook

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Thank you ...