Wilson disease is genetically induced failure of copper metabolism. If untreated, it may lead to death within several years from the onset of symptoms. Use of medication should therefore continue over the whole span of the patient's life after the diagnosis. Clinical observations show that patients with Wilson disease frequently stop the treatment. The aim of our study was to assess how drug compliance (defined as persistence with drug use) translates into the total well-being of patients with Wilson disease.

Patients diagnosed with Wilson disease and observed in our outpatient clinics were asked to fill in the self-completed questionnaire. Questions were related to demographic data, characteristics of the disease, methods of treatment and persistence with treatment, subjective assessment of health status and treatment efficacy. The EQ-5D questionnaire with a visual analogue scale of well-being was also used.

Responses were obtained from 120 subjects but only 104 questionnaires could be further processed. Our analysis did not reveal differences in persistence with d-penicillamine and zinc sulphate use or efficacy of prescribed medication. We found, however, that regardless of the medication used, persistence with treatment resulted in significantly better results of self-assessment (total improvement in 39.7% vs. 7.7% in the non-persistent group, p = 0.003; partial improvement in 53.8% vs. 30.8%, respectively, p = 0.045; and deterioration: none in the persistent group vs. 42.3% in the non-persistent group, p < 0.0001).

Lack of persistence with use of prescribed medication is rather frequent among patients with Wilson disease. Lack of compliance decreases chances for improvement and might be the cause of clinical deterioration.