Nail psoriasis as a severity indicator: results from the PsoReal study

Background: Although nail psoriasis affects a substantial proportion of psoriasis patients and causes significant psychologic distress, few epidemiologic data characterizing patients with nail involvement are available. The aim of this research was to elucidate differences between patients with nail psoriasis and those without any nail involvement, taking quality indicators of health care from the patient's perspective into account. Methods: In total, 2449 patient members of the Deutscher Psoriasis Bund, the largest patient organization for psoriasis in Germany, were interviewed in this nationwide, noninterventional, cross-sectional study. Patients with nail psoriasis were compared with patients without any nail involvement with regard to gender, age, disease duration, affected body surface area, health-related quality of life (Dermatology Life Quality Index [DLQI] ED-5D), patient-defined treatment benefit, amount of inpatient treatments, disease duration, and numbers of work days lost. Results: Data from 2449 patients with psoriasis were analyzed. Overall, 44.8% (1078) of patients were female, mean age was 57.0 +/- 11.7 years, and 72.8% had nail involvement and showed higher values for affected body surface area than those without nail involvement (8.3% versus 5.6%, respectively; P < 0.004). Health-related quality of life was significantly lower in patients with nail psoriasis (DLQI 7.2 versus 5.3; ED-5D 60.1 versus 67.3), who had more days off work (9.8 versus 3.3). Conclusion: Nail involvement is an important symptom of psoriasis and is associated with greater disease severity and quality of life impairment. Accordingly, management of psoriasis should include a special focus on nail involvement.