Digit Preference in Office Blood Pressure Measurements, United States 2015-2019

Abstract

Background: Blood pressure (BP) measurement error may lead to under- or overtreatment of hypertension. One common source of error is terminal digit preference, most often a terminal digit of "0." The objective was to evaluate national trends in terminal digit preference in office BP measurements among adults with treated hypertension.

Methods: Data were from IQVIA's National Disease and Therapeutic Index, a nationally representative, serial cross-sectional survey of office-based physicians. The analysis included office visits from 2015 to 2019 among adults aged ≥18 years receiving antihypertensive treatment. Annual trends were examined in the percent of systolic and diastolic BP measurements ending in zero by patient sex, age, and race/ethnicity, physician specialty, and first or subsequent hypertension treatment visit.

Results: From 2015 to 2019, there were ~60 million hypertension treatment visits annually (unweighted N: 5,585-9,085). There was a decrease in the percent of visits with systolic (41.7%-37.7%) or diastolic (42.7%-37.8%) BP recordings ending in zero. Trends were similar by patient characteristics. However, a greater proportion of measurements ended in zero among patients aged ≥80 (vs. 15-59 or 60-79) years, first (vs. subsequent) treatment visits, visits to cardiologists (vs. primary care physicians), and visits with systolic BP ≥140 or diastolic BP ≥90 (vs. <140/90) mm Hg.

Conclusions: Despite modest improvement, terminal digit preference remains a common problem in office BP measurement in the United States. Without bias, 10%-20% of measurements are expected to end in zero. Reducing digit preference is a priority for improving BP measurement accuracy and hypertension management.

Keywords: blood pressure; blood pressure measurement; hypertension; measurement error; terminal digit preference.