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Prevalence and Costs Associated with Parkinson’s Disease Rising
As the population in the United States ages, there has been an increase in the prevalence of Parkinson’s disease (PD), which has led to physicians focusing on treatment therapies to manage the disease and reduce costs. Lawrence Elmer, MD, PhD, professor in the department of neurology at the University of Toledo College of Medicine, discussed several issues related to PD at the Fall Managed Care Forum in a presentation titled Parkinson’s Disease 2010: Impact on US Health Care and Challenges in Management. Most physicians have difficulty accurately diagnosing PD, according to Dr. Elmer. In fact, he said, primary care physicians correctly diagnose PD 50% to 60% of the time, and PD specialists are accurate in 90% to 92% of the cases. The most common misdiagnosis is in older adults who have shakes and tremors, which does not necessarily indicate they have PD. There are also several Parkinson’s mimics that act like PD but do not share the same pathologies and do not respond to PD therapies. Potential precursors to PD include rapid eye movement sleep behavior disorder, olfaction loss, autonomic dysfunction, depression, and anxiety. Dr. Elmer said it is particularly difficult for physicians to differentiate between dementia with Lewy bodies (DLB) and PD with dementia because DLB has many of the same symptoms as PD with dementia. In PD with dementia, patients’ motor features are impaired within 1 year after diagnosis, the dementia usually develops >8 years after diagnosis, the mean age of onset is younger than in DLB, and the course of the disease is >15 years. In DLB, patients’ motor features are impaired within 3 years after diagnosis, the dementia usually develops <3 years after diagnosis, the mean age of onset is older than PD, and the disease course is <10 years. According to a Parkinson’s Disease Foundation 2007 study, approximately 1 million Americans suffer from PD, although Dr. Elmer said that number may be closer to 2 million to 2.5 million and could increase to 4 million to 5 million in the next 40 years. The prevalence of PD is higher than the combined number of people with multiple sclerosis, muscular dystrophy, and amyotrophic lateral sclerosis. PD is typically found in older people, although 15% of people with PD are diagnosed before age 50. The average age of PD onset is 60 years, and the annual cost of caring for a PD patient is $5000 to $8000. Dr. Elmer said the goal of therapy is to optimize function, minimize complications, and enhance quality of life. According to Dr. Elmer, patients with PD do not suffer much in the first 5 to 7 years but then have motor fluctuations and dyskinesias in the next several years and imbalance and dementia in the advanced stages. Dr. Elmer mentioned several drugs used to treat patients with early-stage PD, including long-acting dopamine agonists (ropinirole XL, pramipexole ER, and rotigotine), slow-acting dopamine agonists (pramipexole and ropinirole), levodopa preparations, rasagiline, selegiline, amantadine, and anticholinergics. In the advanced stages of PD, Dr. Elmer recommended the use of dopamine antagonists (pramipexole, ropinirole, apomorphine, and rotigotine), although he said to be cautious with rotigotine in elderly patients; catechol-O-methyl transferase inhibitors (entacapone and tolcapone), although he said to be cautious of hepatotoxicity; monoamine oxidase beta inhibitors (selegiline, rasagiline, and Zydis selegiline); immediate- and controlled-release carbidopa/levodopa; anticholinergics, although he cautioned use in elderly patients; amantadine; and deep brain stimulation. Dr. Elmer also said researchers are increasingly interested in determining whether nutritional therapy or physical therapy can help patients with PD. Other radical approaches that have been considered and examined include rational polypharmacy and interdisciplinary care. Although past analyses of treatments and outcomes were discouraging, Dr. Elmer said recent studies have suggested changing therapies could enhance lifespan and quality of life while reducing costs.