A Real-World Study on Unstable Parkinson's Disease: Levodopa Dosage Management and the Role of Nonmotor Symptoms

Background: Parkinson's disease (PD) is a neurodegenerative disorder associated with motor and nonmotor symptoms. Objectives: This study assesses levodopa dose management, the therapeutic goals of clinicians, the factors that influence clinicians' choice of therapy, and the role of nonmotor symptoms using real-world evidence from Germany, Italy, and Spain. Methods: To assess the management of unstable PD patients on levodopa-containing regimens, neurologists were asked to complete questionnaires (n = 181) and prospective electronic patient records (EPR) were collected (n = 2687). Neurologists were asked questions about their practice and approach to unstable PD patients. EPRs were completed by neurologists after each visit with patients, and the objectives of any changes to therapy were recorded. Results: Seventy-four percent of neurologists cited "improving motor symptoms" as the main objective for increasing daily levodopa dose. This was also the main objective when starting an add-on (50%) and the main reason for selecting a new add-on therapy (29%). In comparison, reducing nonmotor symptoms, depression, and pain was rarely cited as either the main or secondary objective for a therapy selection (15%, 9%, and 9%, respectively) even when over 60% of unstable patients had pain or depression and 29% had both. When the importance of add-on therapy features was rated, "improve quality of life (QoL)" had the highest average score. Improving nonmotor symptoms, pain, and depression was among the lowest-rated therapy feature. Conclusions: These findings suggest that improving motor symptoms is a key driver of therapeutic choice. In prioritizing motor symptoms, neurologists may unintentionally neglect nonmotor symptoms, despite most patients suffering from pain or depression.