Aims: The present study was conducted to assess the effects of duration of hypertension, systolic hypertension, diastolic hypertension, drug compliance and class-of-drug on cognitive functions.
Methods and results: A cohort of young hypertensive subjects was recruited after obtaining informed consent. Subjects with confounding factors, e.g., substance use, neurological disorders, endocrinopathies, inflammatory conditions, psychiatric illnesses, etc., were excluded. Their average systolic and diastolic blood pressure since onset of illness and prescribed drugs were noted from the records. Compliance was assessed with the help of information from subjects as well as the close relatives. MMSE and a battery of neuropsychological tests (Digit Span Test, Trail Making Test Form B, Stroop Test, Visuospatial Working Memory Matrix and Word Fluency Test) was applied to all the participants. Multivariate regression analysis was used for the assessment of associations and one-way ANOVA was performed to assess differences in the mean. Analysis showed that mean age of study subject was 52 years and average duration of hypertension was 9 years. Fourteen percent subjects had obvious cognitive impairment as suggested by MMSE score less than 23. However, when cut-off score was lowered to 20, only 6% subjects fell into this category. Diastolic blood pressure had significant negative association with all of the cognitive measures except Trail Making Test, which was, on the contrary, significantly and negatively associated with systolic blood pressure. Duration of hypertension did not influence cognitive performance in this study. Effect of drug compliance was somewhat variable, but in general good compliance was associated with better cognitive performance. Beta-Blocker therapy hampered cognitive performance, whereas the best performance, especially on tests of semantic memory and pre-frontal functions was seen in subjects taking calcium channel blockers.
Conclusions: Diastolic hypertension was associated with significant impairment of cognitive functions in younger subjects. On the other hand good compliance and calcium channel blockers had protective effect on hypertension induced cognitive impairment, especially on the prefrontal functions.