Parkinson's disparities

The study is published in the December 13, 2010, online edition of Archives of Neurology.

The cause of these racial and socioeconomic disparities is unclear, but possible explanations include problems with access to health care, reduced physician referral rate or patient reluctance to seek care from a movement disorders specialist. The study focused on a sample of more than 1,000 patients who were seen at the University of Maryland Parkinson's Disease and Movement Disorders Center for parkinsonism (slow movements, tremor and rigidity, difficulty initiating movement, and problems with gait and balance), mostly due to Parkinson's disease, but also caused by other conditions, including stroke, head trauma and medication side effects.

"Through our evaluation over a five-year period, we found that African Americans and people with lower socioeconomic status had greater disease severity and disability than whites when they first came to our clinic. Very large differences in Parkinson's disease symptom severity and functional status were seen between blacks and whites, between high and low income groups and between groups with greater and lesser educational attainment," says Lisa Shulman, M.D., lead author and professor of neurology at the University of Maryland School of Medicine.

"In the future, we will need to see if greater understanding and correction of these disparities could improve outcomes for these patients," adds Dr. Shulman, who is also co-director of the Maryland Parkinson's Disease and Movement Disorders Center at the University of Maryland Medical Center.

The analysis revealed that African American patients were less likely to receive medications for their parkinsonian symptoms overall and less likely to receive newer medications, which are generally more expensive. But the researchers acknowledge that the relatively small number of African Americans in the study (66) may limit their ability to detect differences and that more study is needed.

"The University of Maryland School of Medicine faculty has been at the forefront of tackling issues surrounding health disparities, which is a very complex subject. This study into parkinsonism shows how these disparities can affect all types of medical conditions and why it is important to identify them so we can make sure all patients receive the best care possible," says E. Albert Reece, M.D., Ph.D., M.B.A., vice president for medical affairs at the University of Maryland and dean of the University of Maryland School of Medicine.

The researchers believe this is one of the first studies to show health disparities in disease severity and disability in parkinsonism.

"Future studies need to evaluate patient attitudes and their beliefs about Parkinson's symptoms and treatment. It is possible that some patients may believe slowness and tremor are just part of aging or that they have to reach a certain threshold of severity before seeking treatment. On the other hand, it may be that physicians, either consciously or unconsciously, are less likely to refer African Americans and patients of lower socioeconomic status to a Parkinson's specialist," notes William Weiner, M.D., co-investigator and director of the Maryland Parkinson's Disease and Movement Disorders Center. Dr. Weiner is professor and chairman of neurology at the University of Maryland School of Medicine.

With Parkinson's disease, early medical treatment can have a profound effect on how well a patient functions as the disease progresses. "If treatment for parkinsonism is very delayed, you can't turn back the clock," explains Dr. Shulman.

Dr. Weiner says, "The results of this study show we need to learn more about the causes of parkinsonism and find ways to overcome these disparities, which clearly are affecting the quality of life of patients who are from different backgrounds and means. The differences in function between patients with different education levels may suggest that patients with more education are perhaps more likely to request a referral to a specialist. Conversely, it is possible that physicians are more likely to refer more highly educated patients to a specialist."

The research team, which included physicians and staff from the University of Maryland Department of Neurology, Department of Psychiatry and Department of Epidemiology and Public Health, evaluated patients who came to the Maryland Parkinson's Disease and Movement Disorders Center over a five-year period. Study participants completed questionnaires about their age, race, household income and education as well as how long they had been diagnosed with parkinsonism. They also did self-evaluations on a modified version of the Older Americans Resource and Services Disability Scale, a measurement of the difficulty in performance on 14 daily activities ranging from getting out of bed and getting dressed to cooking meals, using the telephone, handling money and taking medications. Because symptoms of parkinsonism fluctuate, the study participants rated their symptoms twice, describing their best and worst levels of functioning.

The patient assessment included a medical history and neurological examination by a Parkinson's disease specialist. The researchers also used a standard Parkinson's disease scale, the United Parkinson's Disease Rating Scale, to assess the severity of symptoms in all patients.