The Economic and Quality of Life Burden Associated With Parkinson’s Disease: A Focus on Symptoms

Introduction

The incidence and prevalence of Parkinson’s disease (PD) increase with age; with disease duration, both direct and indirect annual costs associated with this disorder will likewise continue to escalate. Given that the population of those 65 years and older is expected to increase from 35 to 80 million by 2040,¹ intensive discussion will focus on healthcare economy, including efficiency, prudent choices by providers, and appropriate allocation of resources. It is anticipated that future treatment of patients with neurodegenerative diseases will require providers to optimize treatment with best available therapies, incorporate disease modification approaches (if available), and emphasize management of healthcare system resources by limiting both direct and indirect expenditures.

Among neurodegenerative diseases, PD especially is associated with a significant economic burden to both patients and society. Over an 8-year span from 1992 to 2000, Medicare beneficiaries with PD used more healthcare services in all categories and had more out-of-pocket expenses than those without this disorder.² While likely due to multifactorial causes, cost of care continues to place an increasing burden on patients with PD, caregivers, and society. This article will address the increasing local and societal burdens associated with the progressive disabilities of PD and will review potential strategies for patient care in an increasingly demanding, cost management–focused environment.

Clinical Features

All clinicians regardless of specialty should have some familiarity with motor and non-motor symptoms related to PD. The 4 cardinal features of PD are well known. Jankovic presented the acronym TRAP in a review paper of the clinical features of PD: Tremor at rest, Rigidity, Akinesia or bradykinesia, and Postural Instability.³ Early in the course of the disease, tremor and other parkinsonian signs are usually asymmetric but eventually become bilateral. Tremor in PD usually occurs at rest about 4 to 7 Hertz in frequency, and may be most noticeable in the arms or hands (“pill-rolling tremor”). Tremor may also involve the chin, jaw, tongue, and legs. Rigidity, or a passive resistance

to movement, may be seen in the neck, shoulder, elbow, wrist, hip, knee, and ankle. Bradykinesia (slowness of movement) affects activities of daily living, including standing, dressing, feeding, brushing teeth, and bathing. Bradykinesia is assessed in the clinic through finger tapping, hand clasping, wrist pronation-supination, and heel tapping maneuvers. Postural instability or loss of postural reflexes is characterized by propulsion or retropulsion and a tendency to fall. Most motor signs in PD are manifestations of these cardinal characteristics: lack of facial expression (hypomimia), sialorrhea, hypophonia, dysarthria, dysphagia, micrographia, shuffling gait, difficulty standing and turning when walking, difficulty turning in bed, start hesitation, freezing, and festination of gait (Table 1).³ The decline in mobility leads to increasing need for assistance and greater economic impact to care for this population.

Patients with PD also commonly develop autonomic dysfunction (orthostatic hypotension, sphincter disturbances, and/or constipation), cognitive changes, psychiatric effects (depression, psychosis, and/or impulse control disorder), sensory symptoms (pain and/or aching), restlessness, and sleep disturbances (Table 1).⁴ These non-motor symptoms are increasingly the focus of care in tertiary neurology clinics. While motor symptoms often benefit from dopaminergic therapies, such as levodopa or a dopamine agonist, non-motor symptoms may result from disturbances of other neurotransmitter pathways, such as cholinergic, serotonergic, or GABA-ergic.⁵ While the combination of motor and nonmotor symptoms in PD increases the options for attaining clinical benefit, these interventions and their potential side effects will also drive up healthcare costs.

Epidemiology

The aging of the world’s population remains the most predictable factor in the increasing economic impact of PD. In 2004, a statewide registry in Nebraska estimated a prevalence of 329 persons with PD per 100,000 people within the total population.⁶ An analysis of prevalence studies estimated the number of people in the United States with PD in 2005 to be 340,000; the authors projected from this that by 2030, with the aging US population, the total number of people with PD would double.⁷ An epidemiologic study of 10 European countries found crude prevalence rates ranging from 66 to 12,500 per 100,000.⁸ The World Health Organization in 2004 estimated that there were approximately 4 million persons worldwide with PD. As the overall world population becomes older, PD prevalence will become greater, resulting in a shift

of healthcare expenditures to a significantly larger proportion spent on the wide spectrum of parkinsonian disorders.

Economic Burden of PD