Postal questionnaire study of disability in the community associated with psoriasis.

OBJECTIVE: To study the disability caused by psoriasis in patients recorded as having psoriasis by their general practitioner.
DESIGN: Postal questionnaire survey using the psoriasis disability index and SF-36.
SETTING: Five general practices in Cleveland.
SUBJECTS: Of 767 patients identified, 546 completed the questionnaire and 435 were eligible and gave informed consent. MAIN OUTCOME MEASURES: Scores on SF-36 and psoriasis disability index.
RESULTS: The psoriasis disability index score was highly negatively correlated with all eight of the SF-36 health measures (P < 0.0001 for each), and the manual social classes scored higher than the non-manual social classes (P < 0.0001). The manual social class group scored significantly lower scores than the controls on all the SF-36 scales, and the non-manual group scored significantly lower for physical and mental role limitation (P < 0.0004 and P = 0.026), mental health (P < 0.0001), energy and vitality (P < 0.0004), and health perception (P < 0.0001). Also, the manual group had poorer health perception on five of the SF-36 variables when compared with the non-manual group.
CONCLUSIONS: Patients with psoriasis have an overall lower perception of their quality of life than healthy controls, and those in the lower social classes suffer a greater degree of disability from their disease than the higher social classes.