VISIT-TO-VISIT BLOOD PRESSURE VARIABILITY AND RISK OF HOSPITALIZATION IN COMMUNITY ELDERLY COHORT

Abstract

Objective: Systolic and diastolic blood pressures (BP) were considered as the main indicators for hypertension. However, the blood pressure variability (BPV) was found to be a potential risk factor for cardiovascular events. The objective of this study was to identify the risk factors of hospitalization based on the visit-to-visit BPV over a year.Design and method: e-Health project is a local multi-centered study to monitor BP in the elderly community. Participants had BP measurement weekly, and all records were stored on the cloud server for real-time analysis. Subjects with at least 30 BP records in the first year of follow-up were included. Visit-to-visit BPV defined as the mean absolute deviation between the BP records and the personalized BP trends fitted using cubic regression. Machine learning approach has been used to stratify the levels of BPV for K-means clustering algorithm on both systolic and diastolic BP. Subjects were classified into low, medium and high levels of BPV groups. The hospitalization was used as the study end-point, and age, gender, mean BP, BPV, multi-medications used, frailty, sarcopenia, and memory function were used as the independent variables. Multivariate logistic regression was used to investigate the associations with the hospitalization in terms of odds ratio (OR) with 95% confidence interval (CI). Results: A total of 1,095 subjects were follow-up for 12 months with average of 163 BP readings per each participant (SD = 74). Age, BPV, use of medications, frailty, sarcopenia, and memory function were shown to be associated with the risk of hospitalization (Table 1). In the multivariate analyses, there were significantly increased risk of hospitalization in the medium and high BPV groups (OR = 1.67; 95% CI = 1.23–2.28 and OR = 2.07; 95% CI = 1.36–3.13, respectively), in the patients prescribed 1–4 and 5 or above medications (OR = 2.39; 95% CI = 1.29–4.86 and OR = 4.05; 95% CI = 2.09–8.51, respectively); in the pre-frail and frail groups (OR = 1.47; 95% CI = 1.04–2.09 and OR = 3.15; 95% CI = 2.11–4.74, respectively). Conclusions: Visit-to-visit BPV, other than comorbid conditions with complex medication used and frailty, is shown to be a risk factor for hospitalization. Regular BP measurement is recommended to better understand BPV levels.