While stroke survivors with higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) measurements are more likely to have worse cognitive performance at 90 days, this association is most likely mediated by sociodemographic and clinical factors, according to study results published in the Journal of Stroke and Cerebrovascular Diseases.
Cognitive decline is commonly seen following stroke and was previously found to be associated with increased disability and mortality. While high blood pressure is associated with late-life cognitive impairment, there are no clear data on the association between blood pressure levels and poststroke cognitive decline. The goal of the current study was to investigate the associations between SBP, DBP, and antihypertensive medication use with cognitive function at 90 days after stroke.
The researchers used data from the Brain Attack Surveillance in Corpus Christi (BASIC) project, a population-based stroke surveillance project in Nueces County, Texas. All participants were required to have measurements of blood pressure and cognitive function at the 90-day in-person outcome assessment.
The study sample included 432 participants aged ≥45 years (median age 66 years, 45% female), most of them were diagnosed with an ischemic stroke and the median National Institutes of Health stroke score was 3.
The primary outcome was the modified Mini-Mental Status Examination (3MSE) and secondary outcomes included the Animal Fluency Test (AFT) to assess executive function and Trail Making Tests A and B divided by completion time to assess visuomotor tracking, information processing speed, divided attention, and cognitive flexibility.
While higher SBP and lower DBP each were significantly associated with lower 3MSE scores, following multiple adjustments for patient factors both did not remain independently associated with 3MSE. Similarly, higher SBP and lower DBP each were significantly associated with worse cognitive performance for AFT, Trails A, and Trails B, but these associations disappeared following adjustment for clinical factors, other than the association between DBP with worse Trails B scores.
Lower cognitive performance was associated with older age, less education, Mexican American ethnicity, diabetes, higher stroke severity, more depressive symptoms, and lower BMI.
Most stroke survivors with hypertension were adherent to anti-hypertensive medication (71%). While there was no association between nonadherence to antihypertensive medication with 3MSE scores, among hypertensive stroke survivors, nonadherence was associated with lower AFT scores, compared to those who adhered to the prescribed medication (adjusted difference, -1.21 points; 95% CI, -2.24 to -0.19; P=.02), but not other tests.
The study had several limitations, according to the researchers, including the cross-sectional design, relatively small sample size, exclusion of a large number of stroke patients due to missing data, limited data on stroke and structural brain features, measurement of blood pressure and assessment of the cognitive outcomes only at 90 days after stroke with no available data on the cognitive function at other time points.
“Stroke survivors’ [blood pressure] levels were not associated with cognitive performance at 90 days independent of sociodemographic and clinical factors”, conclude the researchers.
Levine DA, Galecki AT, Okullo D, et al. Association of blood pressure and cognition after stroke [published online May 1, 2020]. J Stroke Cerebrovasc Dis. doi:10.1016/j.jstrokecerebrovasdis.2020.104754