Baseline demographics and disease characteristics
| Characteristics | FMT (n=15) | Sham (n=16) | Total (N=31) |
| Female sex, n (%) | 8 (53) | 12 (75) | 20 (65) |
| Age, years | 48.9 (16.1) | 52.4 (11.0) | 50.7 (13.6) |
| Height, cm | 175.2 (7.0) | 169.8 (8.6) | 172.4 (8.2) |
| Weight, kg | 93.6 (15.4) | 92.4 (24.8) | 93.0 (20.5) |
| Time since diagnosis, years* | 2.6 (0.3–5.8) | 5.6 (0.5–8.8) | 3.7 (0.5–8.3) |
| Rheumatoid factor IgM negative, n (%)† | 13 (93) | 15 (94) | 28 (93) |
| Anticitrullinated peptide antibody negative, n (%)† | 14 (100) | 16 (100) | 30 (100) |
| HLA-B27 negative, n (%) | 15 (100) | 13 (81) | 28 (90) |
| C reactive protein, mg/L | 4.98 (7.18) | 5.54 (5.87) | 5.27 (6.43) |
| HAQ-DI‡ | 0.89 (0.51) | 0.78 (0.50) | 0.83 (0.50) |
| Swollen joint 66 count | 7.5 (3.0) | 6.7 (2.7) | 7.1 (2.8) |
| Tender joint 68 count | 14.9 (8.9) | 17.3 (8.8) | 16.1 (8.8) |
| SPARCC Enthesitis Index§ | |||
| Score ≥1, n (%) | 13 (87) | 15 (94) | 28 (90) |
| Score in patients with a score ≥1 | 8.1 (4.3) | 7.2 (3.3) | 7.6 (3.8) |
| Dactylitis | |||
| Affected digit(s) ≥1, n (%) | 6 (40) | 4 (25) | 10 (32) |
| Digits affected in patients with affected digit(s) ≥1 | 1.5 (0.5) | 1.5 (0.6) | 1.5 (0.5) |
| Physician’s global assessment of disease activity, VAS¶ | 35.1 (15.8) | 31.4 (13.0) | 33.2 (14.3) |
| Patient’s global assessment of disease activity, VAS¶ | 56.1 (22.3) | 56.0 (23.7) | 56.0 (22.7) |
| Arthritis pain, VAS¶ | 54.1 (23.3) | 48.8 (19.9) | 51.9 (21.3) |
| Fatigue, VAS¶ | 56.5 (26.2) | 57.4 (26.4) | 57.0 (25.9) |
| Presence of nail disease, n (%) | 12 (80) | 10 (63) | 22 (71) |
| PASI** | |||
| Score >0, n (%) | 4 (27) | 6 (38) | 10 (32) |
| Score in patients with a score of more than 0 | 1.07 (2.09) | 1.39 (2.17) | 1.24 (2.11) |
| DLQI score†† | |||
| Score >0, n (%) | 9 (60) | 12 (75) | 21 (68) |
| Score in patients with a score of more than 0 | 2.1 (3.9) | 1.8 (1.7) | 1.9 (2.9) |
| Methotrexate | |||
| Oral administration route, n (%) | 2 (13) | 4 (25) | 6 (19) |
| Oral dose, mg/week | 15.0 (0.0) | 20.0 (4.1) | 18.3 (4.1) |
| Subcutaneous administration route, n (%) | 13 (87) | 12 (75) | 25 (81) |
| Subcutaneous dose, mg/week | 20.0 (4.1) | 20.0 (3.7) | 20.0 (3.8) |
| Previous use of biologic DMARD, n (%) | 2 (13) | 3 (19) | 5 (16) |
| Previous use of non-methotrexate conventional synthetic DMARD, n (%) | 4 (27) | 3 (19) | 7 (23) |
| Antibiotics within 1 year of inclusion, n (%) | 4 (27) | 6 (38) | 10 (32) |
| Positive IgG serology‡‡ | |||
| Yersinia, n (%) | 0 (0) | 1 (6) | 1 (3) |
| Campylobacter, n (%) | 0 (0) | 0 (0) | 0 (0) |
| Salmonella, n (%) | 0 (0) | 1 (6) | 1 (3) |
| Faecal calprotectin, mg/kg§§ | 29 (17–63) | 27 (15–72) | 28 (15–68) |
| Stool frequency per week | 10.4 (3.7) | 10.7 (4.3) | 10.6 (4.0) |
| Bristol Stool Scale score¶¶ | 4.3 (1.3) | 3.6 (1.3) | 4.0 (1.3) |
| Presence of gastrointestinal symptoms within the last week | |||
| Abdominal pain¶ | 14.1 (14.7) | 23.9 (23.4) | 19.2 (20.0) |
| Pyrosis, n (%) | 2 (13) | 2 (13) | 4 (13) |
| Nausea, n (%) | 6 (40) | 3 (19) | 9 (29) |
| Vomiting, n (%) | 1 (7) | 0 (0) | 1 (3) |
| Mucus in the stool, n (%) | 3 (20) | 1 (6) | 4 (13) |
| Blood in the stool, n (%) | 1 (7) | 0 (0) | 1 (3) |
| Smoking status | |||
| Current, n (%) | 5 (33) | 4 (25) | 9 (29) |
| Previous, n (%) | 4 (27) | 8 (50) | 12 (39) |
| Never, n (%) | 6 (40) | 4 (25) | 10 (32) |
| Alcohol consumption, units per week | 0.9 (0.9) | 0.8 (0.6) | 0.8 (0.7) |
Data are mean (SD) or n (%) unless otherwise stated.
*Time since diagnosis of psoriatic arthritis is presented as median and IQR.
†Presence of rheumatoid factor (IgM) and anticitrullinated peptide antibody was not accessed in one patient from the FMT group.
‡HAQ-DI scores range from 0 to 3, with higher scores indicating greater disability.
§SPARCC Enthesitis Index scores range from 0 to 16, with higher scores indicating more severe disease.
¶This evaluation is based on a VAS of 0–100, with higher scores indicating greater disease activity or pain.
**PASI scores range from 0 to 72, with higher scores indicating more severe disease.
††DLQI scores range from 0 to 30, with higher scores indicating more severe disease.
‡‡Serology specification: Salmonella enteritidis and S. typhimurium, Yersinia enterocolitica, and Campylobacter coli and C. jejuni.
§§Median (IQR). Lower detectable limit of faecal calprotectin is 15 mg/g.
¶¶Bristol Stool Scale scores range from 1 to 7, with types 1 and 2 indicating constipation, types 3 and 4 normal, and types 5–7 tending towards diarrhoea (loose to watery stool).
DLQI, Dermatology Life Quality Index; DMARD, disease-modifying antirheumatic drug; FMT, faecal microbiota transplantation; HAQ-DI, Health Assessment Questionnaire Disability Index; HLA-B27, human leukocyte antigen-B27; PASI, Psoriasis Area Severity Index; SPARCC, Spondyloarthritis Research Consortium of Canada; VAS, Visual Analogue Scale.