Our results indicate that pre-stroke educational attainment is an independent predictor of ICH severity and prognosis; those patients with high school only education were 1.61 times more likely to have an ICH volume of greater than 30mL and 2.37 times more likely to have a high ICH score when compared to college diplomates. In our sample, 85.0% of patients had some high school education, with most being high school diplomates (78.3%), and 14.9% of patients were college diplomates. US Census data for educational attainment from 1940 until 2000 was published in 2006 by deciles of age; for adults over the age of 50, the average percentage of high school diplomates was 73.8%24. While more current census data by age decile is not yet available, the percentage of the population with high school diplomas continues to increase; in 2011, 87.6% of people over the age of 25 had high school diplomas which increased to 91.1% in 202125. Our cohort was recruited from 1994 until 2020 and likely represents a slightly more educated population than the national average. However, even in a slightly more educated cohort, the effect of educational attainment impacted stroke severity and prognosis, highlighting the role of social determinants in hemorrhagic stroke.
Despite decades of investigative trials and research in hemorrhagic stroke, few studies have explored the role of educational attainment in a stroke population. One study showed that while higher educational attainment was protective for incident ischemic strokes, the same relationship was not true for hemorrhagic stroke patients26. However, this study examined only 97 total cases of hemorrhagic stroke. Our findings represent a much larger sample and align with previous studies examining the effect of education on all-cause mortality, cardiovascular events, and ischemic stroke9,27.The novel findings that educational attainment impacts ICH severity and prognosis implies two potential mechanisms. First, educational attainment could be a surrogate marker for other social determinants that impact overall health; for example, those with lower education likely had less exposure or access to preventative health services or had more exposures to environments that worsened traditional clinical risk factors4,7, 20–22,27,28. Similarly, those with higher education may have had more exposure to health services through their life course or had more exposures to environments that decreased traditional clinical risk factors. A recent large, international prospective cohort study across 21 diverse countries also found that in 155,722 patients, low education was more predictive of all-cause mortality than hypertension, and contributed just as much, if not more, attributable risk for both cardiovascular and stroke events than tobacco use3.
A second potential mechanism is that educational attainment impacts health literacy and the ability to access, understand, and navigate a complex health system and eventually leads to increased exposure of traditional clinical risk factors or less access to healthcare. For several years, there have been dedicated efforts to implement universal precautions to use plain language in primary care settings to make information more accessible, understandable, and actionable for patients29,30. However, these principles have not yet influenced primary or secondary prevention strategies for stroke. Our finding that educational attainment is associated with stroke severity has important clinical implications for stroke care, health literacy, and health equity and healthcare access for all patients.
Limitations of this study include the relatively homogenous population of patients admitted to MGH; most of our patients are racially white and are classified as middle-income. Our cohort also represents an older population than in previously studied stroke cohorts9,12,13,28,31. However, even in this population, educational attainment was similar to national levels from 1994–2020. Next, we did not record number of years of education for those 170 patients in our sample without high school diplomas. We also did not have this information for the rest of our cohort. We instead chose a dichotomization of educational attainment based on extensive prior research suggesting the dominant dimension of degrees, not years of education, in mortality or disease-specific outcomes. Lastly, a notable finding in our results was that a pre-stroke diagnosis of HTN was an independent predictor of the ICH volume but not ICH score. The limitation of our measure is that HTN is a dichotomous yes/no measure and does not capture the severity or duration of a patient’s hypertension leading to decreased specificity of the value measured.
Future studies should investigate the impact of educational attainment on stroke recovery in more diverse populations, as other social determinants not captured in our cohort could play an impactful role besides educational attainment alone. Next, given that the link between education and stroke risk is now established, future studies should focus on identifying the impact of educational attainment on exposures to traditional clinical risk factors, health care access, and health-related behaviors prior to incident stroke. Our findings demonstrate the need for further research to elucidate the relationship between the social determinants of health in ICH.