| Criteria | CASPAR | Moll and Wright |
| Number of cases | 50 | 54 |
| Male/female ratio | 26/24 (1.08/1) | 29/25 (1.16/1) |
| Median age | ||
| years (range) | 52 (26–79) | 52 (27–79) |
| onset of psoriasis (range) | 28 (2–54) | 28 (2–54) |
| onset of arthritis (range) | 39 (18–63) | 38 (18–63) |
| Median disease duration (range) | 9 (1–49) | 9 (1–49) |
| Proportion with: | ||
| nail involvement | 16/50 (32%) | 30/54 (56%) |
| DIP arthritis* | 16/50 (32%) | 14/54 (26%) |
| polyarthritis (⩾5 joints)* | 15/50 (30%) | 14/54 (26%) |
| oligoarthritis (⩽4 joints)* | 35/50 (70%) | 40/54 (74%) |
| polyarthritis (⩾4 joints)* | 23/50 (46%) | 23/54 (43%) |
| oligoarthritis (⩽3 joints)* | 27/50 (54%) | 31/54 (57%) |
| axial disease† | 5/50 (10%) | 6/54 (11%) |
| axial disease only† | 1/50 (2%) | 1/54 (2%) |
| dactylitis* | 9/50 (18%) | 6/54 (11%) |
| IgM RF positive | 0/50 (0%) | 0/54 (0%) |
| Proportion HLA-B13 positive | 5/41 (12%) | 4/48 (8%) |
| Proportion HLA-B27 positive | 3/41 (7%) | 3/48 (6%) |
CASPAR; CIASsification criteria for Psoriatic ARthritis; DIP, distal interphalangeal (joints); RF, rheumatoid factor.
*At current examination or described in medical records.
†Axial disease was defined as inflammatory back pain and definite uni- or bilateral sacroiliitis on x ray (see text).