Abstract
BACKGROUND: Obtaining accurate blood pressure (BP) readings is a challenge faced by health professionals. Clinical trials implement strict protocols, whereas clinical practices and studies that assess quality of care utilize a less rigorous protocol for BP measurement.
OBJECTIVE: To examine agreement between real-time clinic-based assessment of BP and the standard mercury assessment of BP.
DESIGN: Prospective reliability study.
PATIENTS: One hundred patients with an International Classification of Diseases—9th edition code for hypertension were enrolled.
MEASURES: Two BP measurements were obtained with the Hawksley random-zero mercury sphygmomanometer and averaged. The clinic-based BP was extracted from the computerized medical records.
RESULTS: Agreement between the mercury and clinic-based systolic blood pressure (SBP) was good, intraclass correlation coefficient (ICC)=0.91 (95% confidence interval (CI): 0.83 to 0.94); the agreement for the mercury and clinic-based diastolic blood pressure (DBP) was satisfactory, ICC=0.77 (95% CI: 0.62 to 0.86). Overall, clinic-based readings overestimated the mercury readings, with a mean overestimation of 8.3 mmHg for SBP and 7.1 mmHg for DBP. Based on the clinic-based measure, 21% of patients were misdiagnosed with uncontrolled hypertension.
CONCLUSIONS: Health professionals should be aware of this potential difference when utilizing clinic-based BP values for making treatment decisions and/or assessing quality of care.
References
Perloff D, Grim C, Flack J, et al. Human blood pressure determination by sphygmomanometry. Circulation. 1993;88:2460–70.
McAlister FA, Straus SE. Measurement of blood pressure: an evidence based review. BMJ. 2001;322:908–11.
Pickering TG. What will replace the mercury sphygmomanometer? Blood Press Monit. 2003;8:23–5.
Environmental Protection Agency. Eliminating mercury in hospitals. US EPA Environmental Best Practices for Health Care Facilities. November 2002. www.h2e-online.org. Accessed May 7, 2004.
Jones DW, Appel LJ, Sheps SG, et al. Measuring blood pressure accurately: new and persistent challenges. JAMA. 2003;289:1027–30.
Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;8:307–10.
McGraw K, Wong S. Forming inferences about some intraclass correlation coefficients. Psychol Methods. 1996;1:30–46.
Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7). JAMA. 2003;289:2560–72.
Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159–74.
Author information
Authors and Affiliations
Corresponding author
Additional information
The authors have no conflicts of interest to report.
This study was supported by the Eugene A. Stead Medical Student Research Scholarship to the first author, and an NHLBI Grant R01 HL070713 to the second author.
Rights and permissions
About this article
Cite this article
Kim, J.W., Bosworth, H.B., Voils, C.I. et al. Brief report: How well do clinic-based blood pressure measurements agree with the mercury standard?. J GEN INTERN MED 20, 647–649 (2005). https://doi.org/10.1007/s11606-005-0112-6
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11606-005-0112-6