Quality Improvement in Neurology: 2020 Parkinson Disease Quality Measurement Set Update.

Parkinson disease (PD) is the second most common neurodegenerative disorder, after Alzheimer disease,(1) and the number of individuals with PD worldwide more than doubled between 1990 and 2015.(2) In 2016, PD affected an estimated 6.1 million people globally.(3) In the United States, an estimated 680,000 individuals >= 45 years of age had PD in 2010.(4) These numbers were projected to rise to 930,000 in 2020 and to reach 1,238,000 by 2030.(4) Both motor (rest tremor, bradykinesia, rigidity) and nonmotor (including but not limited to neuropsychiatric, autonomic, and sensory) symptoms of PD contribute to decreased quality of life(5) and neurologic disability.(3)