Probiotic Use and Psoriatic Arthritis Disease Activity

OBJECTIVE: Probiotics have been hypothesized to mediate inflammation through gut microbiome modulation. Spondyloarthropathies have subclinical gut inflammation associated with inflammatory disease that may benefit from probiotic use. We aimed to evaluate associations between probiotic use and patient‐reported outcomes in patients with psoriatic arthritis (PsA). METHODS: Using FORWARD, The National Databank for Rheumatic Diseases, we examined probiotic use among patients with PsA and rheumatoid arthritis (RA), a comparator in which gut inflammation is less clearly related to pathogenesis. Patient‐reported outcome measures such as pain and physical function were compared for probiotic users and nonusers among patients with PsA and RA. Patients were propensity score–matched for taking a probiotic by demographics and nonmedication supplements. RESULTS: More patients have reported probiotic use over the past decade, with less than 1% reporting use in 2008 and approximately 7% in 2018. Probiotic users are more likely to be white women with higher education, income, and supplement use. Following propensity score matching, probiotic users with PsA had significantly lower Short Form 36 Physical Component Summary (SF‐36 PCS) scores and higher pain scores than nonusers with PsA (33.11 ± 11.50 vs. 40.82 ± 11.03; P = 0.04 and 4.78 ± 3.09 vs. 3.00 ± 2.58; P = 0.03). There were no significant differences in Patient Activity Scale II, Health Assessment Questionnaire II, SF‐36 PCS, and Short Form 36 Mental Component Summary scores or pain among users with PsA before and after probiotic initiation. CONCLUSION: We found increasing probiotic use in patients with PsA and important differences between users and nonusers. After accounting for these differences, we found no statistical difference in health outcomes after probiotic use.