Predicting Out-of-Office Blood Pressure in the Clinic (PROOF-BP): Derivation and Validation of a Tool to Improve the Accuracy of Blood Pressure Measurement in Clinical Practice
Sheppard, James P
Hobbs, FD Richard
McManus, Richard J
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Sheppard, J. P., Stevens, R., Gill, P., Martin, U., Godwin, M., Hanley, J., Heneghan, C., et al. (2016). Predicting Out-of-Office Blood Pressure in the Clinic (PROOF-BP): Derivation and Validation of a Tool to Improve the Accuracy of Blood Pressure Measurement in Clinical Practice. Hypertension, 67 941-950. https://doi.org/10.1161/HYPERTENSIONAHA.115.07108
Patients often have lower (white coat effect) or higher (masked effect) ambulatory/home blood pressure readings compared to clinic measurements, resulting in misdiagnosis of hypertension. The present study assessed whether blood pressure and patient characteristics from a single clinic visit can accurately predict the difference between ambulatory/home and clinic blood pressure readings (the ‘home-clinic difference’). A linear regression model predicting the home-clinic blood pressure difference was derived in two datasets measuring automated clinic and ambulatory/home blood pressure (n=991) using candidate predictors identified from a literature review. The model was validated in four further datasets (n=1,172) using Area Under the Receiver Operator Characteristic curve analysis. A masked effect was associated with male sex, a positive clinic blood pressure change (difference between consecutive measurements during a single visit) and a diagnosis of hypertension. Increasing age, clinic blood pressure level and pulse pressure were associated with a white coat effect. The model showed good calibration across datasets (Pearson’s correlation 0.48-0.80) and performed well predicting ambulatory hypertension (AUROC 0.75, 95%CI 0.72-0.79 [systolic]; 0.87, 95%CI 0.85-0.89 [diastolic]). Used as a triaging tool for ambulatory monitoring, the model improved classification of a patient’s blood pressure status compared with other guideline recommended approaches (93% [92-95%] classified correctly; US 73% [70-75%]; Canada 74% [71-77%]; UK 78% [76-81%]). This study demonstrates that patient characteristics from a single clinic visit can accurately predict a patient’s ambulatory blood pressure. Utilisation of this prediction tool for triaging of ambulatory monitoring could result in more accurate diagnosis of hypertension and hence more appropriate treatment.
hypertension, white coat hypertension, masked hypertension, ambulatory blood pressure monitoring, prediction tool
This work was funded by an Medical Research Council (MRC) Strategic Skills Post-doctoral Fellowship (MR/K022032/1) held by JS, with support from a National Institute for Health Research (NIHR) Programme Grant (RP-PG-1209–10051). RJMcM holds an NIHR Professorship and leads the self-management theme of the NIHR Oxford CLAHRC. BW is a NIHR Senior Investigator and his research is supported by the NIHR UCL Hospitals Biomedical Research Centre. FDRH is part funded as Director of the National Institute for Health Research (NIHR) School for Primary Care Research (SPCR), Theme Leader of the NIHR Oxford Biomedical Research Centre (BRC), and Director of the NIHR Collaboration for Leadership in Applied Health Research and Care (CLAHRC) Oxford. The views and opinions expressed are those of the authors and do not necessarily reflect those of the MRC, NHS, NIHR, or the Department of Health.
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External DOI: https://doi.org/10.1161/HYPERTENSIONAHA.115.07108
This record's URL: https://www.repository.cam.ac.uk/handle/1810/253810