African Americans and those with lower socioeconomic status appear to have more severe parkinsonism with greater levels of disability, according to a report posted online today that will appear in the April 2011 print issue of Archives of Neurology, one of the JAMA/Archives journals.

Parkinsonism (slow movements, tremor and rigidity) is a common condition among older U.S. adults, according to background information in the article. "The most common cause of parkinsonism is Parkinson's disease, a debilitating, chronic, progressive neurodegenerative disorder with an incidence rate that increases with age," the authors write. Although racial minorities and those with low socioeconomic status have worse health outcomes for many diseases, including diabetes and Alzheimer's disease, "the effect of race and socioeconomic status on patients with parkinsonism is only beginning to be evaluated."

J. Patrick Hemming, M.D., and colleagues at the University of Maryland, Baltimore, studied 1,159 patients with parkinsonism who were evaluated by movement disorder specialists between 2003 and 2008. In addition to completing a demographics questionnaire, study participants were assessed for their disease severity and level of disability, and their medication use was obtained from their medical history.

Of the participating patients, 93.4 percent were white, 6.1 percent were African American, 61.2 percent earned more than $50,000 annually, 62.7 percent completed college and 79.2 percent had a diagnosis of Parkinson's disease. When compared with white patients, those who were African American tended to have more severe parkinsonism and also greater disability. Lower income and lower educational level were also associated with increased disease severity and disability.

Disparities were observed in treatment patterns as well. African Americans were prescribed fewer medications to treat parkinsonism at their first clinic visit (61.9 percent received medication, compared with 77.6 percent of white patients). Among African-American patients, 20.6 percent were prescribed newer dopaminergic medications (drugs that replace the neurotransmitter dopamine), compared with 41.1 percent of white patients, whereas 12.7 percent of African-American patients received antipsychotic medications compared with 6.1 percent of white patients.

"There was no disparity in the use of antiparkinsonian medications by income or educational level, although lower socioeconomic status groups were also less likely to receive newer agents," the authors write. "This finding suggests that the racial disparity in Parkinson disease management is not fully explained by income or educational level. Other factors may include physician decision-making, patient acceptance of medications and access to care."

"Racial and socioeconomic status disparities are complex phenomena," they conclude. "Parkinsonism reduces quality of life and results in disability and premature mortality [death]. 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."