Variation in blood pressure and mean heart rate predict cognitive dysfunctionLiterature - Böhm M et al., Hypertension 2014
Systolic Blood Pressure Variation and Mean Heart Rate Is Associated With Cognitive Dysfunction in Patients With High Cardiovascular Risk
Böhm M, Schumacher H, Leong D, et al.,
Hypertension. 2015;65:00-00. DOI: 10.1161/HYPERTENSIONAHA.114.04568
BackgroundVisit-to-visit variation in blood pressure (BP) may be linked to stroke and cognitive decline [1,2]. Elevated resting heart rates (HR) have been described to be related to cardiovascular outcomes in hypertension , coronary artery disease  and heart failure [5,6]. HR>76 bpm was related to cardiovascular mortality in patients who experienced a first stroke, as well as with more pronounced cognitive decline after a second stroke .
Little is known about the effect of systolic BP (SBP) visit-to-visit variation, mean HR, and HR visit-to-visit variation on cognitive decline. This article therefore studied the relationship between mean on-treatment SBP, SBP-variation, mean on-treatment HR, and HR-variation and cognitive decline (>5 points reduction in the mini mental state examination (MMSE)) and cognitive dysfunction (<24 points defined as clinically relevant cognitive impairment). Cognitive deterioration was defined as decreasing score of >1 point per year or decline to <24 points. Pooled data of the ONTARGET and the TRANSCEND trials were analysed.
- 1857 patients (7.6%) showed cognitive dysfunction, and cognitive decline was observed in 1176 (4.8%). 1017 patients (4.1%) met the criteria for both endpoints.
- In quintiles of mean SBP, incident cognitive dysfunction increased from 6.0% in the lowest to 9.4% in the highest (P<0.0001). Cognitive decline was seen in 4.0% of patients in the lowest SBP quintile, up to 5.7% in the highest quintile (P=0.0012).
In quintiles of SBP-coefficient of variation (CV), cognitive dysfunction rates increased from 6.3% in the lowest, to 10.2% in the highest quintile (P<0.0001), and cognitive decline ranged from 4.1% to 6.4% (P<0.0001).
Similar increases in the rate of cognitive deterioration were seen in increasing quintiles of SBP (7.4 to 11.2%, P<0.0001) and SBP-CV (7.8 to 12.1%, P<0.0001).
- Similar increasing incidence rates of cognitive decline, dysfunction and deterioration were seen in quintiles of mean HR and HR-CV.
- In a multivariate model, SBP-CV and mean HR were found to be significant predictors of the incidence of cognitive dysfunction, after adjustment for multiple confounders.
An OR for having cognitive dysfunction for the highest vs. the lowest quintile of SBP-CV of 1.32 (95%CI: 1.10-1.58, P=0.0029) was found, and OR: 1.40 (95%CI: 1.18-1.66, P<0.0001) for highest vs. lowest quintile of mean HR.
- The found effects of SBP variation and high mean HR did not differ between patients with or without stroke, nor between patients with or without atrial fibrillation.
ConclusionThese results show that variation in SBP and mean HR are independently related to the development of cognitive decline, incident cognitive dysfunction and cognitive deterioration in high-risk patients with atherosclerosis or after stroke, or high-risk diabetes-mellitus. The effect of mean SBP on cognitive function was not independent of traditional cardiovascular risk factors. These findings indicate that HR and blood pressure variation may help judge the future risk of cognitive dysfunction.
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