Helping Hypertension Patients to Interpret Blood Pressure Readings and Motivate Blood Pressure Control

Not Applicable

Completed

Conditions: Hypertension

Interventions: Other: Communication with enhanced graph
Other: Communication with basic table
Other: Communication with enhanced table

Registration Number: NCT04485637

Lead Sponsor: University of Southern California

Brief Summary: Hypertension is a major risk factor for cardiovascular disease, and a leading cause of death worldwide. Only about 50% of hypertension patients have good blood pressure control, perhaps because they find it hard to understand their blood pressure readings. The investigators will evaluate ways to help hypertension patients to interpret their blood pressure readings and motivate blood pressure control.

Aim 1: Based on existing communications, the investigators will create 3 blood pressure communications:

(A) a basic table showing only the normal blood pressure range, which is often used in clinical practice and online communications about blood pressure, but may make it hard to interpret numbers outside of the normal range, potentially undermining behavior change intentions; (B) an enhanced table showing how combinations of diastolic and systolic blood pressure reflect normal, elevated and hypertension ranges, from the American Heart Association; (C) an enhanced graph to be adapted from Blood Pressure UK to show the same color-coded ranges as the enhanced table, with diastolic blood pressure on the x-axis and systolic blood pressure on the y-axis.

Aim 2: : Among 650 diagnosed hypertension patients recruited through the University of Pittsburgh Medical Center (UPMC) Pitt+Me Patient Registry, the investigators will evaluate whether being presented with the enhanced table or graph (vs. basic table) affects patients' self-reported blood pressure measurement (as averaged across two measurements taken at the time of the survey at least 1 minute apart, as per directions of the American Heart Association), and improves interpretations of these two blood pressure readings and of hypothetical blood pressure readings, as well as behavior change intentions.

Aim 3: The investigators will examine whether Aim 2 findings vary by health literacy, age, and SES.

Detailed Description: BACKGROUND Hypertension is a major modifiable risk factor for cardiovascular disease, and a leading cause of death worldwide. Lifetime risk of hypertension is 70-90%, but it is higher among adults who are older and of low socio-economic status (SES). Older age and lower SES are also associated with low health literacy, which undermines understanding of health information. Yet, low health literacy in hypertension patients is an independent predictor of poor blood pressure control, with only about 50% of hypertension patients having controlled blood pressure. Possibly, patients with lower health literacy find it harder to interpret whether blood pressure readings are high or low, reflect good or bad blood pressure control, and indicate a need for behavior change or medication use. Even college-educated hypertension patients who have bought home blood pressure monitors may struggle to interpret blood pressure readings that are outside the normal range, undermining their intentions to improve their blood pressure control.

BEHAVIORAL SCIENCE INSIGHT Lab studies in behavioral science have found that individuals' ability to interpret numbers (likely including blood pressure readings) is improved by showing the range or distribution - also called 'reference information'. In preliminary work, the PI showed that many people struggle to interpret credit card APRs, because they do not know what numbers are good or bad. In line with the behavioral science insight, the PI found that providing graphs with ranges of existing APRs helped recipients to see which credit cards posed a bad deal, and reduced their intentions to get such credit cards. It has been posited that providing reference information (e.g. normal and abnormal blood pressure ranges) should also help hypertension patients to interpret blood pressure readings, and help them to control their blood pressure.

If reference information is used when communicating blood pressure readings in clinics and online health records, it often involves a basic table that only shows the normal range (e.g., \<120 for systolic and \<80 for diastolic blood pressure). In one behavioral science study, 106 university staff performed similarly when using this basic table or when using a color-coded horizontal bar graph (showing the normal range in white and values outside the normal range in black). However, neither format followed the American Heart Association's communication, which shows more reference information for interpreting blood pressure readings outside of the normal range. Hypertension patients may need to see such enhanced reference information, because they are more likely to encounter blood pressure readings outside of the normal range. Moreover, those readings can be harder to interpret - perhaps especially for hypertension patients with low health literacy. The investigators propose to evaluate 2 formats for providing the more enhanced reference information from the American Heart Association, in either a table (as used by the American Heart Association), or a graph (as used by Blood Pressure UK, to be adapted to show the information from the American Heart Association). The behavioral science literature suggests that tables facilitate reading specific numbers, but that graphs help more with interpreting numbers as high or low, and good or bad - though that could depend on recipients' health literacy.

SPECIFIC AIMS The American Heart Association has called for broad-based efforts to improve the proportion of hypertension patients with controlled blood pressure, by "further engaging individuals in the hypertension control process" with "adequate representation of \[specific\] populations" including those with lower health literacy, older age, and lower SES. Therefore, the investigators propose to conduct an NIH Stage I primary data collection project, to evaluate the efficacy of interventions to facilitate blood pressure readings and motivate blood pressure control, in a sample of hypertension patients varying in health literacy, age, and SES.

Aim 1: Based on existing communications, the investigators' communication expertise (see below), and pilot tests with up to 10 hypertension patients, the investigators will generate 3 blood pressure communications:

(A) a basic table showing only the normal range, which is often used but may make it hard to interpret numbers outside of the normal range, potentially undermining behavior change intentions; (B) an enhanced table with more reference information, showing how combinations of diastolic and systolic blood pressure reflect normal, elevated and hypertension ranges, from the American Heart Association; (C) an enhanced graph to be adapted from Blood Pressure UK to show the same color-coded ranges as the enhanced table, with diastolic blood pressure on the x-axis and systolic blood pressure on the y-axis.

Aim 2:: In a sample of 650 diagnosed hypertension patients recruited through the Pitt+Me Patient Registry at the University of Pittsburgh Medical Center (UPMC), the investigators will evaluate whether being presented with the enhanced table or graph (vs. basic table) affects patients' self-reported blood pressure measurement (as averaged across two measurements taken at the time of the survey at least 1 minute apart, as per directions of the American Heart Association), and improves interpretations of these two blood pressure readings and of hypothetical blood pressure readings, as well as behavior change intentions.

Aim 3: The investigators will examine whether Aim 2 findings vary by health literacy, age, and SES.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 542

Inclusion Criteria

Diagnosed with hypertension
Proficient in English

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Communication with enhanced graph	Communication with enhanced graph	Communication showing an enhanced graph (adapted from Blood Pressure UK) for interpreting blood pressure readings, showing the same color-coded ranges as the enhanced table, with diastolic blood pressure on the x-axis and systolic blood pressure on the y-axis
Communication with basic table	Communication with basic table	Blood pressure communication showing a basic table representing only the normal range of blood pressure readings
Communication with enhanced table	Communication with enhanced table	Communication showing an enhanced table (Fig 1B) with more reference information for interpreting blood pressure readings, including how combinations of diastolic and systolic blood pressure reflect normal, elevated and hypertension ranges (adapted from the American Heart Association)

Primary Outcome Measures

Name	Time	Method
Number of Participants Who Measured Blood Pressure as Instructed (Assessed on Questionnaire)	Questionnaire completed immediately after receiving communication	This outcome measure reflects the number of participants who measured their blood pressure as instructed, after seeing the communication (coded yes=1/no=0), as self-reported on the questionnaire
Number of Participants Who Understood Blood Pressure Readings (Assessed on Questionnaire)	Questionnaire completed immediately after receiving communication	This outcome measure reflects the number of patients who correctly answered two questions about blood pressure readings outside of the normal range, as included on the questionnaire (coded 1=both questions were answered correctly; 0=at least one of the questions was answered incorrectly). The first question asked whether or not blood pressure readings of 132/69 mmHg are considered normal (correct answer=no). The second question asked whether or not blood pressure readings of 142/91 are considered normal (correct answer=no).
Behavioral Intention Index (Provided on Questionnaire)	Questionnaire completed immediately after receiving communication	On a questionnaire, participants indicated how likely it is that they will try to lose weight, exercise more, take medication as recommended, and talk to their health care provider about improving their blood pressure readings, giving a score on a scale ranging from 1 (=very unlikely) to 5 (=very likely). This outcome measure reflects the average score across items.
Evaluation of Blood Pressure Reading (Provided on Questionnaire)	Questionnaire completed immediately after receiving communication	On a questionnaire, participants indicated their perceptions of how healthy they think their own blood pressure is right now, giving a score on a scale ranging from 1(=very unhealthy) to 5 (=very healthy).