Combination Antibiotics Effective in Chlamydia-Induced Reactive Arthritis

Emma Hitt, PhD

April 30, 2010 — A 6-month course of combination antibiotics appears to be effective in treating chronic Chlamydia-induced reactive arthritis (ReA).

"The use of long-term antibiotic treatment for patients with ReA is controversial," according to John D. Carter, MD, from the Division of Rheumatology, University of South Florida, Tampa. "Several reported studies have indicated that prolonged antimicrobial monotherapy is not efficacious...yet other studies suggest there might be a benefit, specifically with Chlamydia-induced ReA."

"[T]his is the first blinded study to indicate a benefit of prolonged combination antimicrobial therapy in patients with chronic Chlamydia-induced ReA," the authors conclude.

Dr. Carter and colleagues conducted a study of 42 adult patients with Chlamydia-induced ReA randomly assigned to 1 of 3 groups: doxycycline 100 mg twice/day plus rifampin 300 mg/day; azithromycin 500 mg/day for 5 days then twice weekly plus rifampin 300 mg daily; or matched placebo.

Patients had disease lasting at least 6 months (mean > 10 years), were determined to be positive based on polymerase chain reaction assessment, and fulfilled the European Spondyloarthropathy Study Group Criteria for ReA. Response to treatment was defined as an improvement of at least 20% in at least 4 of 6 measures, with no worsening in any measure.

After 6 months, 17 (63%) of 27 participants receiving combination antibiotic treatment responded compared with 3 (20%) of 15 patients receiving placebo (P = .01). Secondary endpoints, including modified swollen joint count, tender joint count, and physician global assessment, each showed comparable improvement (P ≤ .002 for all with treatment vs placebo). In addition, there was a trend toward improvement in erythrocyte sedimentation rate in the treated group compared with the placebo group (P = .07).

Of those participants receiving antibiotics, 22% had complete resolution of symptoms compared with none of those receiving placebo. In addition, more treated patients achieved negativity based on polymerase chain reaction (P = .03). Adverse events following treatment were negligible and were comparable with those observed with placebo.

Because of the small study size, it could not be determined which antibiotic combination was most effective, but according to the researchers, patients appeared to achieve the greatest response with the azithromycin plus rifampicin combination.

In a related editorial, Markus Rihl, MD, from the Hannover Medical School, Germany, and colleagues conclude that the study "shows impressive effects and, with them, the potential for the eradication of Chlamydia, which would cure Chlamydia-induced ReA." They add that these findings "represent major steps toward elucidating the etiology of undifferentiated spondylarthritis and toward advancing future management of the disease."

The study was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The editorial was supported by Competence Network Rheumatology, Berlin, Germany.

Arthritis Rheum. 2010;62:1298-1307.

I didnt even know that Chlamidia could cause RA! If this is the case we will see a rise in RA cases as so many young people now carry this disease. I know that I was routinely screened for it when expecting Bernice as it is so common now.

Jenni xx

Hi Jenni

An interesting piece Jenni; just goes to show how much there is that we don't actually know about this group of illnesses. Quite scary really. Thanks for posting the article, always interesting stuff!

Lyn x

I have read that syphilis is very often the cause of Reactive Arthritis, so I suppose it's all the same family of bugs.

When I first saw the Rheumatologist he thought I had reactive arthritis because for the first few months my symptoms were very one sided.
I was a bit put out when I read up on it and discovered it is caused by syphilis!

Doreen xx