Although both antiparkinsonian medications and physical therapy are effective for PD,4 – 6
only about one third of newly diagnosed PD patients were started on therapy. African American patients were significantly less likely to receive treatment for PD than white patients. These differences remained after controlling for other demographic and clinical factors, including age, sex, geography, initial visit with a neurologist, and reason for Medicaid eligibility.
Two recent prospective, observational studies reported that between 39 and 62% of drug-naïve PD patients were started on PD medications within 9 to 12 months.12,13
In comparison, our study found that 30% of PD patients were started on similar treatment. Although this falls at the lower end of the range of the proportion treated, we observed patients for only 6 months after diagnosis and studied a lower socioeconomic group than previously studied.
This study also builds on the small body of literature that describes healthcare disparities in the identification and treatment of PD. Traditionally underserved minorities are less likely to be identified with PD,14
receive therapeutic surgery,15
receive high-quality care,3
or participate in relevant clinical trials.16
Several lessons from the study of depression care may be applicable to our findings. African American patients are less likely to receive treatment for depression than are white patients,17
even though providers are equally likely to recommend treatment. Ethnic minority patients, however, report that they take antidepressant medication less often and find it less acceptable than white patients.18,19
Gaps in the quality of provider communication may also contribute to this disparity.20
Communication patterns during a clinical encounter differ significantly between African American and white patients with depression, which could affect treatment decisions.21
Our data cannot explain whether differences in treatment were due to differences in provider recommendations or differences in patient acceptance of treatment.
This study had the following limitations. First, the use of administrative data does not allow for examination of potential clinical factors that could influence treatment decisions such as disease stage. White patients may be more likely than African American patients to approach Medicaid for care at later stages of illness when other health care options are exhausted, which would select for sicker white patients.
Second, the diagnosis of PD has not been validated in the Medicaid claims. A recent study using Medicare data, however, found high specificity (>99%) and positive predictive value (73%) when using ICD-9 332.0 for PD.22
In addition, we excluded those individuals who were at increased risk for secondary parkinsonism based on a history of stroke, bipolar disorder, or schizophrenia. If misclassification differed between African Americans and white patients, it might confound observed differences.
A third limitation relates to the generalizability of the results. The sample was relatively young, poor, and disabled. The high level of disability (90% of cohort was eligible for Medicaid through Supplementary Security Income) would favor symptomatic treatment among both African American and white patients; however, multiple comorbid conditions that require treatment may discourage clinicians from adding therapies with potential cross-interactions.
Addressing these disparities necessitates increased community, patient, and physician awareness. Understanding the underlying causal mechanisms of these racial disparities such as patient and physician preferences, patient-physician communication, and confounding socioeconomic differences is important to develop interventions to reduce inequities in care and improve health for all patients with PD.