Racial disparities in poststroke activities of daily living (ADL) limitations are not a result of prestroke activity limitations. Instead, according to a recent study, differences appear largest in the first 2 years after stroke (Burke JF, et al. J Stroke Cerebrovasc Dis. 2015;24:1636-1639).
“In this nationally representative study of over 500 stroke patients, there were no racial differences in prestroke ADL limitations. In contrast, marked racial differences in poststroke ADL limitations were observed,” reported James F. Burke, MD, MS, Clinical
Lecturer, Neurology, University of Michigan, Ann Arbor, and colleagues. “Therefore, it is unlikely that the observed racial differences in poststroke ADL limitations are accounted for by differences in prestroke function.”
As Dr Burke explained to Value-Based Care in Neurology (VBCN), it has been well-documented that African American individuals are considerably more likely to have strokes, particularly at younger ages, compared with white individuals. Less understood, however, are differences in outcome by race after stroke.
“The data here suggest that African Americans do a bit worse after stroke, functionally,” said Dr Burke. “When you look at the count of activity limitations, African Americans seem to have somewhere in the ballpark of 20% more limitations than do whites.”
Dr Burke and colleagues tested a simple hypothesis to explain these long-term differences, whether African American patients have more problems at the time of their stroke than do white patients.
“Most of the studies that have seen that African Americans do worse than whites after stroke have been cross-sectional,” Dr Burke said. “But, if you just look at one time point, you cannot tell if that difference emerged at the time of the stroke, or if it is something that had been there for a long time.”
Thus, the researchers used the Panel Study of Income Dynamics, a nationally representative longitudinal panel survey of families and their descendants, to examine differences by race in activity limitations.
All survey respondents who reported an incident stroke between 2001 and 2011 were included in the study. A total of 534 incident strokes were identified, 198 (37%) of them in African American patients.
The primary outcome was an index representing the sum of total ADL limitations (0-7), and the secondary outcome was an index of instrumental ADL limitations (0-6).
No Prestroke Differences in ADL
According to Dr Burke, the researchers found no prestroke racial differences in activity limitations (0.7 vs 0.7; P = .99). In the wave of the incident stroke (between 0 and 2 years from incident stroke), however, African American patients had considerably more ADL limitations than white patients (2.2 vs 1.5; P = .048).
“What we found was that activity limitations that were uncommon in this population prior to stroke became much more common after stroke, and that there was no significant difference by race in terms of activity limitations prior to stroke,” Dr Burke said. “In other words, the number of problems one had before the stroke did not appear to explain the number of problems after the stroke.”
Dr Burke and colleagues are currently using the National Health and Aging Trends Study, which is linked to Medicare claims, to explore alternative hypotheses for why racial differences in poststroke disability may exist. Some possible explanations include poorer access to rehabilitation after stroke, or poorer quality medical care or primary care. Dr Burke also suggested that social factors may have an effect.
“People may be living in environments where they cannot maintain their physical activity as well as you would like,” he said. “They may not be getting as much help in the home either from families or from paid caregivers. It could also be the case that differences in poststroke depression or other psychological factors may have contributed to activity limitations after stroke. The list goes on and on.”
Although the reasons behind this long-term difference remain largely a mystery, for Dr Burke, understanding this problem has far-reaching implications.
“If we learn what is driving this difference, we may be able to reduce racial disparity,” he told VBCN. “We could also take those lessons and apply them to the larger stroke population for stroke survivors more generally.”
