Objective: Nurses are considered to evoke less white-coat hypertension, and might therefore be able to estimate average blood pressure as well as and more conveniently than ambulatory monitoring. The objective of the present study was to determine the correspondence between blood pressure measured by a doctor or a nurse and ambulatory blood pressure.
Design: Hypertensive patients seen in an academic outpatients clinic were selected consecutively. Blood pressure measurements taken under different situations and by different persons were subjected to cross-sectional comparison.
Methods: Average daytime ambulatory blood pressure was compared to blood pressure measured in triplicate by a nurse and by a physician in 110 patients. The value of nurse-measured diastolic blood pressure as a diagnostic test for the detection of white-coat hypertension was compared with ambulatory monitoring as the standard.
Results: Physician-measured diastolic pressure was 3 +/- 11 mmHg (P < 0.05) higher on average than ambulatory pressure, but the difference between nurse-measured and ambulatory diastolic pressure was 0 +/- 12 mmHg (not significant). Systolic pressure measured either by a physician or by a nurse overestimated daytime ambulatory blood pressure by the same amount. For the identification of white-coat hypertension, the sensitivity and specificity of nurse-measured blood pressure were 0.32 and 0.92, respectively, and the positive and negative predictive values were 0.53 and 0.82, respectively.
Conclusions: Nurse-measured blood pressure was not a very reliable indicator of white-coat hypertension, as a negative test was 18% in error. Thus, nurses rather than doctors should routinely measure blood pressure, but nurse-measured blood pressure is not an acceptable substitute for ambulatory monitoring.