Association of Brief Health Literacy Screening and Blood Pressure in Primary Care

Abstract

Health literacy impacts health outcomes. However, the relationship to blood pressure is inconsistent. This study aimed to determine whether health literacy, assessed by clinic staff, is associated with blood pressure among patients with hypertension. The design was a cross-sectional study of a large sample of primary care patient encounters in 3 academic medical center clinics in Nashville, Tennessee. Health literacy was assessed using the Brief Health Literacy Screen, with higher scores indicating higher health literacy. Blood pressure was extracted from the electronic health record. Using 23,483 encounters in 10,644 patients, the authors examined the association of health literacy with blood pressure in multivariable analyses, adjusting for age, gender, race, education, and clinic location. Independent of educational attainment, 3-point increases in health literacy scores were associated with 0.74 mmHg higher systolic blood pressure (95% CI [0.38, 1.09]) and 0.30 mmHg higher diastolic blood pressure (95% CI [0.08, 0.51]). No interaction between education and health literacy was observed (p = .91). In this large primary care population of patients with hypertension, higher health literacy, as screened in clinical practice, was associated with a small increase in blood pressures. Future research is needed to explore this unexpected finding.

Acknowledgments

Author contributions were as follows: design (David E. Willens, Courtney Cawthon, Lorraine C. Mion, Sunil Kripalani, and Christianne L. Roumie), conduct/data collection (Courtney Cawthon, Corinne Davis, and Ioana Danciu), analysis (David E. Willens, Ken Wallston, Jonathan S. Schildcrout, and Corinne Davis); drafting manuscript (David E. Willens); and critical revision of manuscript (David E. Willens, Jonathan S. Schildcrout, Courtney Cawthon, Ken Wallston, Lorraine C. Mion, Corinne Davis, Ioana Danciu, Russell L. Rothman, Sunil Kripalani, and Christianne L. Roumie). Protocol and statistical code are available from David E. Willens on request.

The authors acknowledge the resources and use of facilities at VA Tennessee Valley Healthcare System Geriatric Research, Education and Clinical Center (GRECC), Nashville, Tennessee.

This material is based on work supported by the Department of Veterans Affairs-Office of Academic Affiliations with resources and the use of facilities at VA Tennessee Valley Healthcare System, Nashville TN (David E. Willens, Ken Wallston, Lorraine C. Mion, Christianne L. Roumie); VA Geriatric Research, Education and Clinical Center (David E. Willens, Ken Wallston, Lorraine C. Mion, Christianne L. Roumie); Vanderbilt University Innovation and Discovery in Engineering and Science Program Grant Award; Award R21 HL096581 (Sunil Kripalani) from the NHLBI. Russell L. Rothman is a consultant for Abbott Diabetes Care and Pfizer, Inc.

Russell L. Rothman is a consultant for Abbott Diabetes Care and Pfizer, Inc.

Sunil Kripalani is a consultant for PictureRx, LLC, and Pfizer, Inc.

Notes

Note. BHLS = Brief Health Literacy Screen, HS = high school, IQR = interquartile range, mmHg = millimeters mercury.

Note. *BP < 140/90 mmHg or < 130/80 mmHg among patients with diabetes.

BP = blood pressure, IQR = interquartile range, mmHg = millimeters mercury, BHLS = Brief Health Literacy Screen.

The BHLS sum and age were mean-centered before fitting these models at 12 and 65, respectively. The intercepts for the systolic BP and diastolic BP models represent the expected or mean value for the population of people who have a BHLS score equal to 12, are 65 years old, White, female, have a high school or equivalent education only, and were seen at Clinic A.

Note. BHLS = Brief Health Literacy Screen, DBP = diastolic blood pressure, HS = high school, mmHg = millimeters mercury, SBP = systolic blood pressure.

*p ≤ .001. †p ≤ .01.

Note. BHLS = Brief Health Literacy Screen, HS = high school, IQR = interquartile range, mmHg = millimeters mercury.

Note. BHLS = Brief Health Literacy Screen, BP = blood pressure, IQR = interquartile range, mmHg = millimeters mercury, HS = high school.

*BP < 140/90 mmHg or < 130/80 mmHg among patients with diabetes.

The BHLS sum and age were mean-centered before fitting these models at 12 and 65, respectively. The intercepts for the systolic BP and diastolic BP models represent the expected or mean value for the population of people who have a BHLS score equal to 12, are 65 years old, White, female, have a high school or equivalent education only, and were seen at Clinic A.

BHLS = Brief Health Literacy Screen, BP = blood pressure, HS = high school, mmHg = millimeters mercury.

*p ≤ .001. †p ≤ .01. ‡p ≤ .05.