A review of blood pressure measurement protocols among hypertension trials: implications for "evidence-based" clinical practice.

Hypertension guidelines recommend following published standardized protocols to obtain accurate blood pressure (BP) readings in clinical practice. However, the various measurement techniques among clinical trials that provide the basis for evidence-based management have not been evaluated or compared with guideline recommendations. We reviewed published information regarding BP measurement in clinical trials (n = 64) from 1990-2014 by searching PubMed and Google Scholar databases. Every trial failed to provide published information regarding at least one of the 10 methodological aspects we evaluated. Details regarding the health-care provider(s) performing measurement(s), temporal-relation to last medication dosage, number of readings, resting time before (and between recordings), and the device(s) used varied among the trials and often differed from clinical recommendations. Most studies did evaluate ≥2 BP readings in a seated position, presumably from the upper arm (although explicit acknowledgment of this latter detail was rare). When indicated, "trough" BP levels were most commonly obtained (15 of 16 trials), whereas the usage of automated devices increased over time. Numerous aspects of BP measurement varied considerably across trials and often from most recent guideline recommendations. The lack of uniform methodologies in outcome studies that form the foundation of evidence-based guidelines may have significant clinical implications.