Objective: To assess the prevalence of Parkinson’s disease (PD) among African- Americans compared to non-Hispanic Whites in a tertiary urban Movement Disorders center. Background: Contributing factors in the prevalence of Parkinson’s disease (PD) based on race may improve health disparities in the United States. According to the largest study analyzing prevalence and incidence of PD among Medicare beneficiaries, the ratio of African-Americans (AA) to Caucasians in the general Medicare population is 9%, while the prevalence ratio of PD among AA compared to Caucasians is approximately 5%. Methods: We performed a retrospective analysis of African-American patients with PD in the movement disorders database at Boston Medical Center, which is the largest safety net hospital in New England. The demographics of the patients seen in the general neurology clinic are 30.57% AA and 38.06% non-Hispanic Caucasian. Results: The Movement disorders database included 488 patients, 327 of whom had PD. Of these, 287 were Caucasians and 18 were of African descent. Based on our clinic population the expected PD case ratio among AA compared to Caucasians was approximately 49%. The actual race ratio in patients of African descent compared to Caucasian was 6%, which was substantially lower than expected at Boston Medical Center. Conclusion: The demographics of the PD patients in our movement disorders clinic do not reflect the population at Boston Medical Center, or the demographics of our neurology clinic as a whole.
Parkinson’s disease (PD) is a progressive neurodegenerative disorder diagnosed primarily by clinical presentation and neurological examination. The prevalence of PD among the elderly population is approximately 1.6% [
The difference in incidence rate of PD in AA compared to whites has not been explained so far by insurance, income, location of care, or healthcare utilization. Further analyses have been recommended to find other potential causes, such as patient, physician and system factors. There have also been several studies analyzing patient perception and knowledge of PD among racial and ethnic groups. African-Americans were less likely to report PD related disability compared to whites based on a small sample size of PD patients using the Unified Parkinson Disease Rating Scale (UPDRS) [
However, under-reporting of PD symptoms does not entirely explain disparities in PD treatment [
Boston Medical Center is the largest safety net hospital in New England, as 59% of the population it serves is disadvantaged due to lack of access to care, race, ethnicity and social factors. The proportions of Blacks or AA and Whites or Caucasians in the population seen at the hospital were respectively 29.1% and 33.6% in 2011. The demographics of patients seen in the general neurology clinic are similar to the overall population at Boston Medical Center (AA 30.57% and Caucasians 38.06%) (
RACE | N | Total % |
---|---|---|
Asian | 324 | 7.95% |
American Indian/Native American | 91 | 0.69% |
Black/African American | 4034 | 30.57% |
Declined/Not Available | 3703 | 28.10% |
Hispanic or Latino | 4 | 0.03% |
Native Hawaiian/Pacific Islander | 15 | 0.11% |
White | 5022 | 38.06% |
(blank) | 1 | 0.007% |
valence of PD by race, age, sex and county, reported that the prevalence ratio of PD among African-Americans compared to Caucasians in the general Medicare population is about 5%.
Data were abstracted from the movement disorders database from the Boston University Neurology Department. The database includes patients seen in the outpatient neurology clinic who have a known diagnosis of Parkinsonism. Data recorded include demographics, race, ethnicity, date of onset of symptoms, date of diagnosis and insurance. Racial demographics are divided into ethnicity including African-Black, -North and American-Black. The diagnosis is confirmed by a Movement Disorders specialist within the neurology clinic at Boston Medical Center. The ratio of cases in the database was compared to the Medicare population-based study of Parkinson’s disease [
The prevalence ratio of PD among AA compared to Caucasians in the general population is about 9% based upon the Willis article. The expected case ratio in our population was determined by multiplying the prevalence ratio of AA compared to Caucasians at Boston Medical Center in 2016, by the PD prevalence ratio of AA compared to Caucasians based on the Willis article. This expected rate was compared to the actual case ratio of AA compared to Caucasians with PD in our database.
Of the 488 patients were in the movement disorders database, 327 patients were diagnosed with idiopathic PD and 161 were diagnosed with other neurological disorders. There were 45 patients of African descent (sub-Sahara, northern- Africa and African-American) in the database. Of these 45 patients, 18 or 40% were diagnosed with idiopathic PD. There were 393 Caucasian patients in the database. Of these, two hundred and eighty seven or 73% were diagnosed with idiopathic PD (
Calculation of the expected case ratio was based upon the Willis et al. study, which demonstrated a prevalence ratio for PD of 0.58 [
Although this study provided a larger proportion of Africans-Americans compared with non-Hispanic Caucasians than other studies analyzing the prevalence ratio of patients with Parkinson’s disease [
RACE | Without iPD | With iPD | Total |
---|---|---|---|
African-American* | |||
African-Black (Sub-Sahara) | 6 | 2 | 8 |
African-North (Sahara or Northern Regions: Algeria, Egypt, Morocco, Tunisia, Etc.) | 2 | 2 | 4 |
American-Black (African descent, originating in: Canada, Caribbean, Brazil, US, etc.) | 19 | 14 | 33 |
American Indian/Alaska Native | 0 | 2 | 2 |
Asian-East (China, Japan, Korea, etc.) | 4 | 8 | 12 |
Asian-West (Bangladesh, India, Iran, Iraq, Pakistan, etc.) | 4 | 2 | 6 |
Caucasian | 106 | 287 | 393 |
Mixed Race | 1 | 0 | 1 |
Native Hawaiian or Other Pacific Islander | 0 | 1 | 1 |
Not in EMR (Declined/Not Available) | 0 | 1 | 1 |
Other―No category above reflects origin | 4 | 0 | 4 |
Spanish (Cuban, Iberian Peninsula, Mexican, South or Central American, or Other Spanish Origin) | 15 | 8 | 23 |
*African-American, including African-Black (Sub-Sahara); North (Sahara or Northern regions: Algeria, Egypt, Morocco, Tunicia, etc.); American-Black (African descent, originating in: Canada, Caribbean, Brazil, US etc.).
Patient Demographics | ||
---|---|---|
Gender | Women | 50.2% (245) |
Men | 49.7% (243) | |
Race | Caucasian | 80.5% (393) |
African American: | 9.2% (45) | |
American-Black (African descent, originationg in: Canada, Carribean, Brazil, US, etc.) | 6.8% (33) | |
African-Black (Sub-Sahara) | 1.6% (8) | |
African-North (Sahara or Northern Regions: Algeria, Egypt, Morocco, Tunisia, etc.) | 0.8% (4) | |
Spanish (Cuban, Iberian Peninsula, Mexican, South or Central American, or Other Spanish Origian) | 4.7% (23) | |
Asian: | 3.7% (18) | |
Asian-East (China, Japan, Korea, etc.) | 2.5% (12) | |
Asian-West (Bangladesh, India, Iran, Iraq, Pakistan, etc.) | 1.2% (6) | |
Other―No category above reflects origin | 0.8% (4) | |
American Indian/Alaska Native | 0.4% (2) | |
Mixed Race | 0.2% (1) | |
Native Hawaiian or Other Pacific Islander | 0.2% (1) | |
Not in EMR (Declined/Not Available) | 0.2% (1) | |
Education | Bachelor's degree | 25.8% (126) |
Graduate or Professional degree | 21.1% (103) | |
High School degree/GED | 20.9% (102) | |
Not Documented | 14.1% (69) | |
Some College, no degree | 8.4% (41) | |
3.9% (19) | ||
Some High School, bo degree | 3.7% (18) | |
Associate degree | 2.0% (10) | |
Occupation | Not in the Labor Force | 69.1% (337) |
Management, Professional, Related | 12.3% (60) | |
Sales | 5.9% (29) | |
Not Documented | 4.5% (22) | |
Service | 4.1% (20) | |
Construction, Extraction, Maintenance | 2.3% (11) | |
Production, Transport, Material Moving | 1.8% (9) | |
Insurance | Medicare or Medicaid | 53.3 % (260) |
Private | 35.7% (174) | |
Not Documented | 7.4% (36) | |
Free care | 2.7% (13) | |
Self pay | 1.0% (5) |
the patients were examined and diagnosed by movement disorders specialists.
The dominant contributing factors in the prevalence of Parkinson’s disease (PD) include age, sex, race and geographic location [
Boston Medical Center is also a tertiary hospital and provides care to a large proportion of AA. Therefore, it is expected that the Movement Disorders group at Boston Medical Center would also care for a large proportion of AA with PD, even taking into account the smaller incidence and prevalence of PD in that population. However, this is not the case based upon the analysis of our movement disorders database. Many of the patients with idiopathic PD are Caucasian and the observed ratio of AA with PD (6% vs 49% expected) is much lower than expected. This may suggest referral bias among physicians at Boston Medical Center, which may cause an under-diagnosis of PD among African-Americans.
A recent systematic review of the literature analyzing racial disparities in PD analyzed the differences in PD diagnosis and treatment among AA compared to non-Hispanic Caucasians [
Our results further support Dahodwala et al.’s conclusion that racial differences in PD are not due to the clinical needs or appropriateness of care [
Branson, C.O., Quehl, L., James, R., Weinberg, J., Hohler, A.D. and Saint-Hilaire, M.-H. (2017) Racial Demographics in an Urban Movement Dis- orders Clinic. Advances in Parkinson’s Dis- ease, 6, 86-92. https://doi.org/10.4236/apd.2017.63009