Essential factors influencing health-related-quality of life in psoriasis.

BACKGROUND: The negative impact of psoriasis on health related quality of life (HRQoL) has been well documented. An unanswered question is the relative contribution of different manifestations of psoriasis (skin, joint, nail involvement) to HRQoL.

AIM: To assess the relative contribution of the different symptom domains on HRQoL in psoriasis.

METHODS: 165 psoriasis patients (41.2 % with psoriasis arthritis (PsA)) were enrolled in a single-center cohort-study. For the assessment of HRQoL, patients completed EuroQoL (EQ-5D), the Short Form 36-item Health Survey (SF-36), the Health Assessment Questionaire (HAQ), and Dermatological Life Quality Index (DLQI) questionnaires. Multiple regression analysis was applied to determine the contribution of the measured parameters to the EuroQoL score (used as a reference measure for overall HRQoL).

RESULTS: Psoriasis arthritis (PsA) patients showed a higher impairment in all HRQoL measures than the patients without PsA. PASI, number of affected joints (PsA-score), DLQI and HAQ were significant predictors of HRQoL (R2=0.57). HAQ was the dominant contributor to HRQoL, both in patients with PsA and without PsA (partial eta 0.23 and 0.28, respectively). Final model with improved R2 (0.61) was obtained by backward regression analysis, and included 6 parameters: PASI, PsA-score, and three questions from HAQ and one question from DLQI questionnaire.

CONCLUSION: Musculoskeletal symptoms are an essential component of HRQoL in psoriasis, even in patients without active PsA. A model consisting of PASI, PsA-score, and 4 questions derived from DLQI and HAQ seems to reflect total HRQoL impairment in psoriasis. This finding may further optimize drug therapy in psoriasis.