Background: To examine the effect of probiotics as adjunctive therapy for the treatment of rheumatoid arthritis (RA). A sample size of 30 subjects was calculated to determine a moderate effect.
Material/Methods: A three month double-blind, placebo-controlled study was performed using probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 capsules administered orally. Inclusion criteria required at least 4 swollen and 4 tender joints and stable medications with no steroids for at least 1 month prior to and during the study. Twenty-nine patients with RA were randomized to treatment. ACR20 responses, serum cytokine levels and safety parameters were assessed.
Results: Fifteen patients were randomized to the probiotic group, and 14 to placebo. Three subjects in the probiotic (20%) and one in the placebo group (7%) achieved an ACR20 response (p= 0.33). There was no statistically significant difference between individual components of the ACR20 criteria. Changes in cytokines favored placebo over probiotic. There was a significant improvement in the Health Assessment Questionnaire (HAQ) score in the probiotic group from visit 1 to visit 3 (p=0.02) but no between-group differences.
Conclusions: Due to inclusion criteria, patients selected for the study had stable RA with chronic synovitis, and thus it may have been difficult for an adjunctive therapy to demonstrate improvement within 3 months. Although probiotics did not clinically improve RA as measured by the ACR20, it is interesting that there was functional improvement seen within the probiotic group compared to placebo.

Keywords: Placebos, Pilot Projects, Inflammation Mediators - blood, Double-Blind Method, Cytokines - blood, Arthritis, Rheumatoid - drug therapy, Antirheumatic Agents - therapeutic use, Probiotics - therapeutic use, Questionnaires