Deep breathing: A simple test for white coat effect detection in primary care

Abstract

Aim. White coat hypertension (WCH) is hard to differentiate from sustained hypertension without the use of 24-h ambulatory blood pressure monitoring (ABPM). This invaluable procedure is nevertheless cumbersome and expensive. A simple test of deep breathing over 30 s (DBT) was proposed as a method to unveil WCH. Methods. Two hundred and fourteen outpatients referred for the evaluation of uncontrolled hypertension (blood pressure, BP > 140/90 mmHg despite therapy) were enrolled in a controlled clinical trial. The examinees were randomly divided in two groups: control (n = 108; sequential standard BP measurement only) and intervention (n = 106; the same+DBT), using ABPM as the reference standard. Results. The relative decrease in BP was significantly larger in the intervention group than in the control group, by 15/4 mmHg (p = 0.005). The best detection of WCH was obtained at ≥ 15% systolic BP reduction following DBT, with a positive predictive value of 94.0% (95% CI 72.0–100.0). BP reduction of ≤ 8% may rule WCH out with a negative predictive value of 78.4% (95% CI 64.0 – 85.9). Conclusion. DBT is a reliable, inexpensive and fast test for the detection of WCH in primary care.

Key Words::

• Ambulatory blood pressure monitoring
• deep breath test
• white coat hypertension

Acknowledgements

We are grateful for the expertise, suggestions and help in statistical evaluation of data to Maja Jeličić and Žarko Bajić from Biometrika Healthcare Research, Zagreb, Croatia.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.