Turner MJ et al. (2006) Lack of sphygmomanometer calibration causes over- and under-detection of hypertension: a computer simulation study. J Hypertens 24: 1931–1938

Poorly calibrated sphygmomanometers could lead to clinically significant errors in hypertension detection, over and above errors introduced as a result of random intra-individual blood pressure (BP) variability. To determine the proportion of error attributable to inadequate sphygmomanometer calibration, Turner et al. carried out a computer simulation study.

The investigators modeled BP measurements in a population of 15 million adult Australians using 17,000 calibrated and 17,000 uncalibrated sphygmomanometers. The simulation showed that, as the number of visits to the clinician increased, the proportion of hypertension-detection error attributable to uncalibrated sphygmomanometers also increased; the effect of this source of error was partially obscured by random BP variability when the number of consultations in an individual was small. After three patient visits, poorly calibrated sphygmomanometers accounted for 20% of undetected systolic and 28% of undetected diastolic hypertension (BP >140/90 mmHg) and for 15% of falsely detected systolic and 31% of falsely detected diastolic hypertension. The model indicated that error attributable to poor sphygmomanometer calibration is more likely to compromise detection of hypertension in young adults (18–24 years old) and women.

More frequent and rigorous calibration of sphygmomanometers by accredited organizations would be a cost-effective way of improving the accuracy of hypertension detection.