UCSF

Background

Aging is accompanied by an overall dysregulation of many dynamic physiologic processes including those related to blood pressure (BP). While year-to-year BP variability is associated with cardiovascular events and mortality, no studies have examined this trend with more frequent BP assessments. Our study objective is to take the next step to examine week-to-week BP dynamics-pattern, variability, and complexity-before death.

Methods

Using a retrospective study design, we assessed BP dynamics in the 6 months before death in long-term nursing home residents between 1 October 2006 and 30 September 2017. Variability was characterized using SD and mean squared error after adjusting for diurnal variations. Complexity (i.e., amount of novel information in a trend) was examined using Shannon's entropy (bits). Generalized linear models were used to examine factors associated with overall BP variability.

Results

We identified 17,953 nursing home residents (98.0% male, 82.5% White, mean age 80.2 years, and mean BP 125.7/68.6 mm Hg). Despite a slight trend of decreasing systolic week-to-week BP over time (delta = 7.2 mm Hg), week-to-week complexity did not change in the 6 months before death (delta = 0.02 bits). Average weekly BP variability was stable until the last 3-4 weeks of life, at which point variability increased by 30% for both systolic and diastolic BP. Factors associated with BP variability include average weekly systolic/diastolic BP, days in the nursing home, days in the hospital, and changes to antihypertensive medications.

Conclusions

Week-to-week BP variability increases substantially in the last month of life, but complexity does not change. Changes in care patterns may drive the increase in BP variability as one approaches death.