Table 1 Response rates in cases versus controls
Cases*n = 163Controls†n = 505
Incorrect address12 (7.3)179 (34.0)
Eligible to respond151 (92.6)326 (64.5)
Non-responders26 (17.2)163 (50.0)
Responders
    initial67 (44.3)97 (29.8)
    delayed58 (38.4)72 (22.1)
    total125 (82.7)163 (50.0)
Onset of joint symptoms not verified by patient27
Final group for analysis from eligible subjects98 (64.9)163 (50.0)
  • *Cases: patients with psoriatic arthritis with onset within the past 5 years.

  • †Controls: patients with psoriasis with no history of inflammatory arthritis.