Objectives: To determine whether there are differences between blood pressure (BP) measured by the nurse (NBP), BP measured by the physician (PBP) and self-measured BP in treated hypertensive patients and, if found, to evaluate their clinical importance.
Method: An observational study is carried out with hypertensive patients recruited from two village-based community health centres in Catalonia (Spain) serving an area with a total population of 2800 inhabitants. All patients treated for hypertension visiting the health centre on a specific day of the week and during the same timetable between October 2000 and May 2001 were included.
Results: The difference between physician-systolic BP and nurse-systolic BP was 5.16 mmHg (95% CI 2.62-7.7; p<0.001). The difference between physician-systolic BP and self-measured systolic BP was 4.67 mmHg (95% CI 0.89-8.44; p=0.016). The differences between nurse-systolic BP and self-measured systolic BP were not significant (0.49 mmHg; 95% CI 3.71-2.71; p=0.758). With regards to diastolic BP, no significant differences were found between the different ways of measurement. NBP gave the following values: sensitivity (Sn) of 92% and specificity (Sp) of 60%; positive predictive value (PPV) of 65.7% and negative predictive value (NPV) of 90% with a positive coefficient of probability (CP+) of 2.3 and a negative coefficient of probability (CP-) of 0.133. PBP gave the following results: Sn=72%; Sp=66.7%; PPV=64.3%; NPV=74.1%; CP+=2.16 and CP- = 0.420.
Conclusion: Systolic BP measured by the nurse in treated hypertensive patients is significantly lower than the readings obtained by the physician, and are almost identical to ambulatory BP monitoring. Blood pressure determination by the nurse is desirable not only for diagnosis but also to evaluate the level of control of blood pressure during the follow-up of treated hypertensive patients.