Baseline demographics and disease characteristics of healthy controls (HC), FMT donors, and patients with psoriatic arthritis (PsA)
| Characteristic | HC (n=31) | FMT donors (n=4) | PsA patients (n=31) |
| Female sex, number (%) | 20 (65%) | 2 (50%) | 20 (65%) |
| Age, year | * | 37.8 (10.0) | 50.7 (13.6) |
| Body mass index (kg/m2) | – | 23.8 (1.4) | 31.4 (7.2) |
| Time since diagnosis, year† | – | – | 3.7 (0.5 to 8.3) |
| Rheumatoid factor IgM negative, number (%)‡ | – | – | 28 (93%) |
| Anti-citrullinated peptide antibody negative, number (%)‡ | – | – | 30 (100%) |
| HLA-B27 negative, number (%) | – | 4 (100%) | 28 (90%) |
| HAQ-DI§ | – | – | 0.83 (0.50) |
| Swollen joint 66 count | – | – | 7.1 (2.8) |
| SPARCC enthesitis index¶ | – | – | |
| Score≥1, number (%) | – | – | 28 (90%) |
| Score in patients with a score≥1 | – | – | 7.6 (3.8) |
| Tender point count | – | – | 6.8 (4.6) |
| C-reactive protein, mg/L | – | 5.27 (6.43) | |
| Methotrexate | |||
| Oral administration route, number (%) | – | – | 6 (19%) |
| Oral dose, mg/week | – | – | 18.3 (4.1) |
| Subcutaneous administration route, number (%) | – | – | 25 (81%) |
| Subcutaneous dose, mg/week | – | – | 20.0 (3.8) |
Data are mean (SD) or n (%) unless otherwise stated.
*Age of each HC corresponds to a patient matched within a 5-year age intervals: 20–24, 25–29, 30–34, 35–39, 40–44, 45–49, 50–54, 55–59, 60–64, and 65–69. Only one (71-year old) patient was matched with a HC in a lower age category (interval 65–69), since blood donors are retired when they turn 70 years. The lower age limit for HC would be 20–24 years while the upper range limit would be 64–69 years.
†Time since diagnosis of PsA is presented as median and IQR.
‡Presence of rheumatoid factor (IgM) and anti-citrullinated peptide antibody was not accessed in one patient from the FMT group.
§Scores on the Health Assessment Questionnaire Disability Index (HAQ-DI) range from 0 to 3, with higher scores indicating greater disability.
¶SpondyloArthritis Research Consortium of Canada (SPARCC) Enthesitis Index range from 0 to 16, with higher scores indicating more severe disease.
DMARD, disease-modifying anti-rheumatic drug; FMT, faecal microbiota transplantation.