African Americans with parkinsonism have more severe symptoms, more disability, and poorer symptom management than whites, according to a report published online Dec. 13 in the Archives of Neurology.
These disparities cannot be attributed to differences between the races in age, cognitive function, or disease duration since these factors were comparable between blacks and whites in this single-center study. It appears that the racial disparities "may be explained by delayed diagnosis, referral patterns, access to care, economic factors, or a combination of all of these," wrote Dr. J. Patrick Hemming and his associates at the University of Maryland, Baltimore (Arch. Neurol. 2010 Dec. 13 [doi:10.1001/archneurol.2010.326]).
Independently of race, both lower socioeconomic status and lower education level also were associated with more severe signs and symptoms, greater disability, and poorer management of parkinsonism in this study, which the investigators described as "the first to show health disparities in disease severity and disability in parkinsonism."
"Studies in different patient populations and geographic locations are necessary to confirm these findings," they noted.
In their study, Dr. Hemming and his colleagues evaluated 1,090 patients with parkinsonism who were participating in a quality of life assessment at the university’s movement disorders center between 2003 and 2008. A total of 66 patients were African-American and the rest were white; the researchers were unable to assess patients of other racial or ethnic backgrounds.
African Americans scored an average of 10 points higher on the Unified Parkinson’s Disease Rating Scale than did whites (53 vs. 42.8). The investigators called this finding a "striking difference that may influence mortality" because a previous study found that a one-point increase on the UPDRS scale was associated with a relative risk ratio of 1.1 for death within 7 years.
African Americans also had worse scores than did whites on a modified version of the Older Americans Resource and Services (OARS) disability subscale, which measures the level of difficulty in performing 14 daily activities.
Significantly fewer African Americans were prescribed antiparkinson medications than were whites (62% vs. 78%), and fewer African Americans also were receiving new dopaminergic agents (21% vs. 41%). In contrast, significantly more black patients used antipsychotic medications than did whites (13% vs. 6%).
When the data were analyzed by income and education level after controlling for race, UPDRS and OARS scores were significantly higher among patients who earned less than $30,000 per year than among those who earned more than $70,000 per year.
Similarly, low-income patients used newer dopaminergic agents significantly less often than did high-income patients (30% vs. 47%). Low-income patients, however, were more likely to be prescribed antidepressants, antipsychotics, and antidementia agents.
Newer dopamine agonists were prescribed significantly less often for patients with less than a college education (35%) than for those with a college education (43%). In contrast, antipsychotics were approximately twice as likely to be prescribed for patients without a college education (8.4%) as they were for those with a college education (4.7%).
These findings reinforce the conclusion that racial disparities in the management of parkinsonism are not solely due to differences in income or education level, but that race itself is a significant independent factor, Dr. Hemming and his associates said.
"The results of this study suggest we need to better understand the cause of parkinsonism and to find remedies for disparate outcomes among patients with parkinsonian disease who are of different backgrounds and means," they noted.
It is possible that African Americans or their physicians have a higher threshold for seeking specialized treatment for parkinsonian signs and symptoms. "Studies have shown that African Americans and other minorities may perceive common medical conditions as natural processes that do not require medical intervention," the investigators wrote.
In addition, they suggested that "physicians may be influenced by unconfirmed reports that Parkinson’s disease is less common in African American populations."
Future studies should examine patient and physician attitudes and beliefs about symptoms of and therapies for parkinsonism, Dr. Hemming and his associates added.
Dr. Hemming’s associates reported ties to numerous manufacturers of drugs for Parkinson’s disease.