Socio-demographic and clinical factors influencing the adherence to treatment in Parkinson's disease: the ADHESON study

Background: Symptoms of Parkinson's disease (PD) are usually controlled by a continuous titration of medication and addition of multiple therapies over the course of the disease. Therapeutic complex schemes, polymedication, comorbidities and the number of medications required contribute to non-adherence. Methods: This cross-sectional survey was performed in 418 patients with PD on treatment with any antiparkinsonian medication. Patient adherence was assessed through physicians' subjective perception and the Morisky-Green test (MGT). Several social, demographic and clinical features were correlated through bivariate and multivariate analyses. Results: According to the physician's opinion 93.7%, and according to the MGT 60.4% of patients were adherent to parkinsonian therapy. The bivariate analysis showed greater adherence in patients with a high level of knowledge about the disease (62.8%), good clinical control (63.6%), a spouse or life partner (63%) and higher incomes (66%). Negative correlation with psychiatric symptoms was found. In relation to the MGT, the logistic regression model showed a negative correlation between cognitive deterioration and psychiatric pathology and adherence to therapy. Conclusions: The physician's impression overestimated the compliance of patients when compared with an objective evaluation such as the MGT. Cognitive impairment and psychiatric symptoms are the clinical variables associated with a lower level of adherence.