Impact of psoriasis on health-related quality of life decreases over time: an 11-year prospective study.

Although psoriasis typically affects patients for many years, studies quantifying impairment in health-related quality of life (HRQOL) owing to psoriasis over long periods are lacking. This study, which interviewed patients independent of psoriasis care, investigates change in the impact of psoriasis on HRQOL over 11 years and factors associated with change among 484 patients using the Impact of Psoriasis Questionnaire (IPSO). We determined changes in the impact of psoriasis on HRQOL using a psychometrically optimized version of the IPSO. In 1993, the patients were 53+/-11.4 years and 61.8% males. From 1993 to 2004, impact on most social aspects of HRQOL remained stable, but concerns related to physical appearance decreased (e.g., 36-13%, P = 0.001). Over 11 years, the proportion of patients with low overall impact of psoriasis increased significantly (43-53%, P < 0.001). Mean IPSO scores (range 0-22) decreased by one-fifth (5-4, P < 0.001). At follow-up, patients reporting poor health had mean improvement in HRQOL about three times greater than those in good health (P < 0.05). In this large cohort interviewed independent of treatments and psoriasis status, impact of psoriasis on HRQOL decreases over time. For chronic diseases, HRQOL is best measured over time and independently of seeking treatment.