Efficacy and safety of probiotic supplementation in psoriatic arthritis - a randomized controlled trial
In brief
Probiotics did not outperform placebo for psoriatic arthritis activity
After 12 weeks, 43% of probiotic recipients reached low disease activity or remission, compared with 65% on placebo; the difference was not statistically significant. The trial also found no clear changes in gut markers or microbiome, and no serious product-related harms, but its 66 participants leave the effects of probiotics uncertain.
- Journal
- Rheumatology (Oxford, England) (Q1)
- Published
- 5 October 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Philipp Bosch, Angelika Lackner, Barbara Dreo, Johannes Fessler, Florentine Moazedi-Fürst, Rusmir Husic, et al.
- PMID
- 42832303
- DOI
- 10.1093/rheumatology/keag547
Why clinicians should know about it
- Picked for Rheumatology (top studies of the week, 11 October 2026): Placebo‑controlled RCT of probiotic in PsA
Abstract
OBJECTIVES: To evaluate the clinical efficacy and safety of a multispecies probiotic in patients with psoriatic arthritis (PsA) in moderate disease activity. METHODS: In this single-centre, randomized, double-blind, placebo-controlled trial (RCT), 66 PsA patients with moderate disease activity (Psoriatic Arthritis Disease Activity Score [PASDAS] >3.2 to < 5.4) on stable immunomodulatory therapy were randomized 1:1 to receive either a multispecies (Lactobacillus, Bifidobacterium) probiotic or placebo for 12 weeks. The primary outcome was treatment response at week 12, defined as achieving low disease activity or remission (PASDAS ≤3.2) without treatment change. Secondary outcomes included gut permeability markers, immune cell and microbiome composition. Analyses were conducted per a modified intention-to-treat (only complete cases for primary outcome), with sensitivity analyses using multiple imputation, per-protocol datasets, and qPCR-based detection of the probiotic strains in stool (adherence). RESULTS: Fifty-six participants were included in the main analysis. Thirteen (43%) participants in the probiotic group and 17 (65%) in the placebo group achieved the primary outcome (p = 0.167). The corresponding odds ratio was 0.4 (95% CI 0.13 to 1.18). Patient-reported pain and global assessment were the main PASDAS components improving over time, with no between-group differences. No differences were observed in secondary clinical outcomes, gut permeability markers (zonulin, calprotectin, alpha-1-antitrypsin), immune cell profiles, or stool microbiome composition between groups at week 12. No serious adverse events related to the study product were reported. CONCLUSION: In this first RCT investigating probiotic supplementation in PsA, probiotic treatment did not show superiority over placebo in achieving treatment response, or altering gut microbiome, or permeability.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.