Randomised, blinded, placebo controlled trial of doxycycline for chronic seronegative arthritis

Objective-To determine whether long term doxycycline improves symptoms in p atients with chronic seronegative or reactive arthritis. Methods-A randomised, triple blind, controlled clinical trial of three mont hs' treatment with doxycycline or placebo of patients with chronic reactive or seronegative arthritis was conducted. The primary study end points were three month pain and functional status measured by a self administered Art hritis Impact Measurement Scales version 2 (AIMS2) quality of life question naire. Secondary end points were pain and functional status at 6-12 months, three month rheumatologist assessed joint count, pain, and arthritis activ ity, and treatment efficacy in those with previous exposure to chlamydia. Results-Of 60 patients randomly allocated to receive doxycycline or placebo , results from 37 were evaluable at three months. Groups were well balanced for major prognostic variables. Doxycycline had no detectable effect at th ree months on pain change scores (mean difference 1.5, 95% CI -1.2 to 4.2, p=0.25) or composite functional change scores (mean difference 0.8, 95% CI -5.6 to 7.1, p=0.81). Furthermore, there were no differences in secondary s tudy end points, and no apparent treatment effect in patients with previous chlamydia infection. Conclusion-Three months' treatment with doxycycline did not improve pam or functional status in patients with chronic reactive or seronegative arthrit is.