A recent Scientific Reports study assessed whether clinically derived measures of heart rate variability (HRV) and blood pressure variability (BPV) are associated with the manifestation of Alzheimer’s Disease and Related Dementias (ADRD).
Study: Blood pressure variability supersedes heart rate variability as a real-world measure of dementia risk. Image Credit: Andrii Vodolazhskyi / Shutterstock
Background
Previous studies have established a link between cardiovascular measures of autonomic dysfunction and ADRD manifestation. Considering this association, these studies have proposed a method to detect individuals at a higher risk of developing cognitive dysfunction.
A higher BPV is one of the most prominent factors associated with the incidence of ADRD. To obtain BPV data, frequent blood pressure measurements spanning over many years are required. One of the challenges of obtaining BPV data is that most clinical practices do not follow the required high-fidelity protocols to measure blood pressure. Therefore, it is important to evaluate whether the BPV generated using clinical practice data offers similar valuable information regarding ADRD risk prediction.
Therefore, while promising, it remains unclear if BPV derived from clinically generated blood pressure data may offer similar or even any valuable information with respect to ADRD risk stratification in a real-world clinical care setting.
Besides BPV, HRV can also be considered to determine cognitive dysfunction. In contrast to BPV, HRV can be generated using a much shorter period of data. The Multi-Ethnic Study of Atherosclerosis (MESA) study indicated an association between higher HRC and better cognitive performance. Compared to blood pressure assessment, electrocardiogram (EKG) ascertainment is less prone to measurement error. However, compared to the rate of blood pressure assessment, EKG is performed much less frequently.
To prevent ADRD development, it is imperative to develop cost-effective and accurate tools for identifying people at higher risk of ADRD. This strategy will also help identify people who are at an early stage of cognitive dysfunction and offer clinicians more time to design effective treatment plans to delay disease progression.
About the Study
This study assessed the potential of BPV and HRV in predicting the risk of ADRD. All relevant data linked to the clinical assessment period of 2013-2016 was obtained from the electronic health record (EHR) of a large academic medical center in Southern California.
For the study cohort, the age, sex, smoking status, and ethnicity of the selected participants were obtained. Furthermore, information about the comorbidities of the participants, such as chronic kidney disease, diabetes mellitus, atrial fibrillation or flutter, myocardial infarction, coronary artery disease, heart failure, cancer metastases, and stroke, was collected.
Participants with a history of ADRD or less than 18 years of age were excluded from the cohort. From this cohort, patients with HRV were identified based on EKG reports. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the selected participants were obtained to estimate BPV.
Study Findings
A total of 48,204 patients fulfilled all eligibility criteria and were considered in this study. Although blood pressure measurements were obtained for all patients, EKG of only 7270 patients were noted.
The average age of participants in the blood pressure cohort was 54.9 years, and most of this cohort was female. Several comorbidities commonly prevailed in this cohort, namely, diabetes mellitus, heart failure, kidney disease, and coronary artery disease. During the clinical assessment period, each patient had an average of 15.4 blood pressure measurements. Their mean SBP was ~124 mmHg, and DBP was ~73.8 ± 7.2 mmHg. Around 28.1% of the cohort was prescribed with at least one antihypertensive drug.
The average age of the EKG cohort was 68.1 years, and the majority of participants of this cohort were female. The most common comorbid condition identified in the EKG cohort was coronary artery disease, followed by heart failure, diabetes mellitus, and atrial fibrillation/flutter. Participants underwent around 23.9 blood pressure measurements in the clinical assessment period, and average SBP and DBP were estimated to be 11.8 mmHg and 73 mmHg, respectively. In this cohort, 46.1% of participants were prescribed at least one antihypertensive medication.
The current study observed that in comparison to HRV, BPV derived from real-world, i.e., clinically generated data, were robustly associated with the incidence of ADRD across sex and age strata. This finding implies that BPV can be effectively used to identify patients at a higher risk of developing ADRD. Previous studies have indicated that high BPV and low HRV were linked with neurovascular damage, which could lead to cognitive dysfunction.
Conclusions
In contrast to HRV, the clinically derived BPV was found to be a more potent marker of ADRD risk. Therefore, BPV can be used for screening of ADRD risk. However, a better understanding of the dynamic combinations of different risk traits linked with ADRD is needed over the life course. This information could help develop a better strategy for ADRD management.
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