The characteristics and outcomes of patients who make an emergency department visit for hypertension after use of a home or pharmacy blood pressure device

Background — Emergency department visits for hypertension are rapidly rising. Hypertension guidelines began recommending use of self-measurement blood pressure (BP) devices in the early 2000s, which could be contributing to the rise. We aimed to examine the proportion of emergency department visits for hypertension that occurred after a BP measurement with a self-measuring device, and the associated outcomes.

Methods — This retrospective observational study included adults who made an emergency department visit with a primary diagnosis of hypertension at one of five community and tertiary hospitals in Ontario, Canada, between April 2010 and March 2011. We categorized emergency department visits into four groups: those made after a home BP reading, a pharmacy reading, secondary to a physician referral, and all others (termed “not documented”). We examined rates of admission to hospital, emergency department treatment (administration of antihypertensive medication, prescription provision), and post-ED clinical events (follow-up care, return emergency department visits, and long-term all-cause mortality) by group.

Results — Among 1508 qualifying patients, median presenting emergency department BP was 182/97 (IQR 164-200/85-109). The percentage of patients who presented to the emergency department after a reading at home, at a pharmacy, via physician referral, and the remaining “not documented” patients was 40.9%, 8.3%, 13.3% and 37.5%, respectively. Overall 109 (7.2%) patients were admitted to hospital. The proportion of patients admitted after a home or pharmacy reading, a physician referral, or “not documented” was 3.1%, 11.9%, and 11.0%, respectively. Two-year mortality rates were 5.4%, 0.0%, 6.5% and 5.3% for the home, pharmacy, physician referral, and “not documented” groups, respectively. Among the 92.3% of patients who were discharged from the emergency department, 11% made another emergency department visit for hypertension within a year.

Conclusions — In this study half of patients with an emergency department visit that was primarily for hypertension came following elevated readings on self-measurement devices. Only 3% of these patients were admitted to hospital.