Long-term disability and prolonged sick leaves as outcome measurements in ankylosing spondylitis. Possible predictive factors.

Prognostic factors for the occurrence of longterm disability and prolonged sick leave were determined in 182 patients with ankylosing spondylitis. A significant relationship appeared between functional disability (determined by the Stanford Health Assessment Questionnaire) and sex, age at disease onset, and the number of peripheral joints involved. Using a life-table approach, the probability of prolonged sick leaves was associated with peripheral joint involvement and work that involved carrying heavy loads. Long-term disability was more frequent after work involving exposure to cold conditions (relative risk [RR] = 2.01) and prolonged standing postures (RR = 1.34), while sedentary work (RR = 0.35) and formal vocational rehabilitation programs (RR = 0.57) seemed to protect against long-term disability.