Table 4 Subclassification in current and previous studies on psoriatic arthritis
Number of casesMedian arthritis duration (years)Proportions (%)*
DIPA†OA‡ ⩽4PA§ ⩾5OA‡ ⩽3PA§ ⩾4AD¶
Population-based studies
    Current study549(26)722655432 (10)
    Alenius et al (2002)21**67045314531(22)
Hospital-based studies
    Wright et al (1959)2**1185701570155
    Roberts et al (1976)44**16817791779(5)
    Kammer et al (1979)8**1001354255425(21)
    Scarpa et al (1984)14628163913 (21)
    Gladmann et al (1987)7220916 (54)21612 (34)
    Torre-Alonso (1991)15**180(50)444144417 (23)
    Helliwell et al (1991)125020014786
    Veale et al (1994)101004(34)45494
    Jones et al (1994)45100121(27)26636
    Salvarani et al (1995)384611591713
    Marsal et al (1999)467315476414
    Kane et al (2003)221294(39)48292
    Madland et al (2005) 24634110 (36)2969(13)
  • AD, axial disease; DIP, distal interphalangeal (joints); DIPA, distal interphalangeal arthritis; OA, oligoarthritis; PA, polyarthritis.

  • *Percentage with arthritis mutilans is not shown. Explains why some proportions does not add up to 100%. †DIP involvement solely—all with DIP involvement in parenthesis. ‡Number of affected joints specified. §Number of affected joints specified (includes symmetrical and asymmetrical). ¶Axial arthritis solely—all with axial involvement in parenthesis. **No information on the number of joints defining OA versus PA. Results are underlined.