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Race and Ethnicity Associated With Health-Related Quality of Life in Parkinson Disease
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Findings from a recent published study observed lower quality of life in Black, Hispanic, and Asian patients with Parkinson disease compared with White patients.
Daniel Di Luca, MD
In a recently published cohort study in Neurology,findings showed that among patients with Parkinson disease (PD), Black, Hispanic, and Asian patients had significantly lower health-related quality of life than White patients.1 These results suggests that some of the quality-of-life differences might be mediated by cognitive status and provides further understanding in outcomes across non-White patient populations as race and ethnic minorities have been underrepresented in PD research.
Scores on the 39-item PD questionnaire (PDQ-39), used to evaluate quality of life, were significantly higher in minority groups compared with White non-Hispanic patients after the adjustment of sex, age, and disease duration (P <.001). The total average score was 29 for Black patients, 27 for Hispanic patients, 25 for Asian patients, and 23 for white patients. Notably, cognitive scores were higher in White patients when compared to other racial and ethnic groups as measured by Z-scores (Black, 0.08 [±0.74] vs. -0.2 [±0.74]; Asians, -0.11 [±0.77]; Hispanics, -0.07 [±0.73]).
“Previous research has shown that some populations may have limited access to neurologists, medications and other therapies. Our study found that Black, Hispanic, and Asian patients with PD do have a lower quality of life than white patients, and that some health disparities and management differences persist even with ongoing expert neurologist care,” lead author Daniel Di Luca, MD, movement disorders fellow at the Toronto Western Hospital, University of Toronto in Canada, said in a statement.1
In this retrospective, cross-sectional study, patients were evaluated at PD Foundation Centers of Excellence and asked to complete the PDQ-39. The study included 8,514 patients with PD (white, 90% [n = 7,687]; Hispanic, 6% [n = 495]; Asian, 2% [n = 170]; Black, 2% [n = 162]) who had at least one visit between 2009 and 2020. To investigate differences between racial and ethnic groups, a multivariable regression analysis was adjusted for sex, age, disease duration, Hoehn and Yahr (H&Y) Stage, comorbidities and cognitive score. Also, a multivariable regression with skewed-t errors was performed to assess the patient's contribution of each variable to the association of PDQ-39 with race and ethnicity.
In the PDQ-39, participants were asked to complete questions about how often they had trouble with physical daily tasks (e.g., housework, cooking or getting around in public) during the past month. Additionally, patients answered questions about mental status, including feelings of being anxious, depressed, ignored by others or unable to communicate properly. In the scores for mobility, emotional well-being, social support and pain, all were also significantly worse for Black, Hispanic, and Asian patients than for White patients.
the inclusion of cognitive scores significantly reduced the strength of association of PDQ-39, race and ethnicity for minority groups in the longitudinal analysis. Thus, minority patients had an overall lower cognitive score compared with White patients. Notably, in the mediation analysis, cognition partially mediated the association between race, ethnicity, and PDQ-39 scores (proportion mediated, 0.251; P <.001). Researchers also observed that thinking and memory tests accounted for some of the differences in quality-of-life scores between Black, Hispanic, Asian, and White patients.
Limitations in the study included that the data only contained records from patients treated at the PD Foundation Centers of Excellence, making it not generalizable to the overall care of PD patients globally. Also, the small sample size of non-White, non-Hispanic patient populations, which limited the ability to observe small but potentially critical differences. Researchers did not have comprehensive neuropsychological assessments despite their access to detailed clinical characteristics. Additionally, they did not have the full details on the social determinants of health and did not adjust the final analysis by level of education.
“Evaluating the underlying reasons behind differences in quality of life between racial and ethnic groups is crucial to improve care,” Di Luca said in a statement.1 “Future studies are needed to gain a better understanding of the reasons for treatment and outcome differences in underrepresented populations, including differences in thinking and memory, clinical care and quality of life.”
REFERENCES
1. For people with Parkinson’s disease, quality of life linked to race, ethnicity. News Release. American Academy of Neurology. Published April5, 2023. Accessed April 13, 2023. https://www.aan.com/PressRoom/Home/PressRelease/5069
2. Di Luca DG, Luo S, Liu H, et al. Racial and Ethnic Differences in Health-Related Quality of Life for Individuals with Parkinson Disease Across Centers of Excellence. Neurology. 2023;10.1212/WNL.0000000000207247. doi:10.1212/WNL.0000000000207247
