Combination antibiotics as a treatment for chronic Chlamydia-induced reactive arthritis: a double-blind, placebo-controlled, prospective trial

Abstract

Objective: Chlamydia trachomatis and Chlamydophila (Chlamydia) pneumoniae are known triggers of reactive arthritis (ReA) and exist in a persistent metabolically active infection state in the synovium, suggesting that they may be susceptible to antimicrobial agents. The goal of this study was to investigate whether a 6-month course of combination antibiotics is an effective treatment for patients with chronic Chlamydia-induced ReA.

Methods: This study was a 9-month, prospective, double-blind, triple-placebo trial assessing a 6-month course of combination antibiotics as a treatment for Chlamydia-induced ReA. Eligible patients had to be positive for C trachomatis or C pneumoniae by polymerase chain reaction (PCR). Groups received 1) doxycycline and rifampin plus placebo instead of azithromycin; 2) azithromycin and rifampin plus placebo instead of doxycycline; or 3) placebos instead of azithromycin, doxycycline, and rifampin. The primary end point was the number of patients who improved by 20% or more in at least 4 of 6 variables without worsening in any 1 variable in both combination antibiotic groups combined and in the placebo group at month 6 compared with baseline.

Results: The primary end point was achieved in 17 of 27 patients (63%) receiving combination antibiotics and in 3 of 15 patients (20%) receiving placebo. Secondary efficacy end points showed similar results. Six of 27 patients (22%) randomized to combination antibiotics believed that their disease went into complete remission during the trial, whereas no patient in the placebo arm achieved remission. Significantly more patients in the active treatment group became negative for C trachomatis or C pneumoniae by PCR at month 6. Adverse events were mild, with no significant differences between the groups.

Conclusion: These data suggest that a 6-month course of combination antibiotics is an effective treatment for chronic Chlamydia-induced ReA.

Trial registration: ClinicalTrials.gov NCT00351273.

Figure 1

A. Modified Swollen Joint Count Legend: P-values: *=0.0001; **<0.0001; #=0.0007; ##=0.0005 Fig 1A: Modified swollen joint counts in subjects on combination antibiotics versus placebo. There is a statistically significant difference at months 1, 3, 6, & 9. B. Tender Joint Count Legend: P-Values: *=0.0009; **<0.0001; #=0.002; ##=0.0004 Fig 1B: Tender joint counts in subjects on combination antibiotics versus placebo. There is a statistically significant difference at months 1, 3, 6, & 9.