In Determining Blood Pressure, More Measurements Improve Accuracy
A single measurement doesn’t correctly classify a patient’s hypertensive status, according to an Annals of Internal Medicine study.
Department of Veterans Affairs researchers followed some 450 patients with hypertension. Over 18 months, systolic pressures were determined from home recordings, routine clinical visits, and scheduled research-associated visits. When examined by method of measurement, 28% of patients were within BP control limits according to routine clinical measurements, 47% according to home measurements, and 68% according to research-visit measurements.
When examined by frequency of measurement, within-patient variances (usually about 10%) decreased dramatically when two or more measurements were made, although there was little benefit beyond five or six measurements. The advantage of repetition held across all methods of measurement.
The authors call for use of averaged home readings to ensure high-quality care. Editorialists, citing the widespread prevalence of sloppy technique, review the proper method and also advocate use of BP measurement as a performance metric.
