Delayed Parkinson's disease diagnosis among African-Americans: the role of reporting of disability.

BACKGROUND/AIMS: Racial differences in the observed prevalence of Parkinson's disease (PD) may be due to delayed diagnosis among African-Americans. We sought to compare the stage at which African-American and white PD patients present for healthcare, and determine whether perception of disability accounts for racial differences.
METHODS: Using records of veterans with newly diagnosed PD at the Philadelphia Veterans Affairs Medical Center, we calculated differences in reporting of symptoms as the difference in z-scores on the Unified Parkinson Disease Rating Scale part 2 (disability) and part 3 (motor impairment). Ordinal logistic regression was used to determine predictors of stage at diagnosis.
RESULTS: African-American (n = 16) and white (n = 58) veterans with a mean age of 70.1 years were identified. African-Americans presented at a later PD stage than whites (median Hoehn + Yahr stage 2.5 vs. 2.0, p = 0.02) and were more likely to under-report disability relative to motor impairment (81 vs. 40%, p < 0.01). Multivariate analysis showed that under-reporting of disability accounted for much of the effect of race on stage of diagnosis.
CONCLUSIONS: Under-reporting of disability among African-Americans may account for later stages of PD diagnosis than whites. This study begins to explain the mechanisms underlying observed racial disparities in PD.