The “white coat effect” is smaller for blood pressure measurements made by nurses than by doctors, and the difference is enough to trigger more diagnoses of hypertension, reported a study from the UK.
In the meta-analysis, 15 studies (11 for hypertensive populations; 4 for mixed hypertensive and normotensive populations) were included for adults reporting mean blood pressures measured by doctors and nurses at the same visit. Results appeared online in the British Journal of General Practice.
Nurse-measured blood pressures were lower than that of doctors. The weighted mean difference for systolic blood pressure was –7.0 mm Hg (95% CI, –4.7 to –9.2). The weighted mean difference for diastolic blood pressure was –3.8 mm Hg; (95% CI, –2.2 to –5.4). White coat hypertension was diagnosed more frequently based on doctors’ than on nurses’ readings (relative risk, 1.6; 95% CI, 1.2 to 2.1).
The findings support a decade-old statement that suggesting stopping using high blood pressure readings documented by general practitioners to make treatment decisions.
“New 2013 European guidelines also still regard office blood pressure measurement as the ‘gold standard’ for screening, diagnosis and managing hypertension,” the authors wrote. “Although the UK 2011 guidelines promote use of home or ambulatory blood pressure readings for diagnosis, entry to the diagnostic pathway for hypertension relies initially on surgery-based readings, thus the risk of misclassification and inappropriate treatment with inaccurate initial blood pressure readings remains a clinical concern if doctors are systematically recording higher blood pressures than nurses.”
An editorial stated that office-based blood pressures are an entry point for further evaluation, since nurse-led readings do not eliminate the problem of white coat hypertension. Home or ambulatory monitoring can help.
“Self-monitoring or even self-management with self-titration may become the preferred approach, given the potential for patient empowerment, enhanced adherence, and reduction in workload,” the editorial stated. “Given that around one-third of people with hypertension now self-monitor, such an approach is becoming more feasible although the inability to prescribe sphygmomanometers and the logistics of ensuring regular checks or recalibration of patients’ own devices are issues which will need to be broached.”