Predicting Out-Of-Office Blood Pressure (Proof-BP) in the clinic for the diagnosis of hypertension in primary care: an economic evaluation

Clinical guidelines in the US and UK recommend that individuals with suspected hypertension should have ambulatory blood pressure (BP) monitoring (ABPM) to confirm the diagnosis. This approach reduces misdiagnosis due to white coat hypertension but will not identify people with masked hypertension who may benefit from treatment. The Predicting Out-of-Office Blood Pressure (PROOF-BP) algorithm predicts masked and white coat hypertension based on patient characteristics and clinic BP, improving the accuracy of diagnosis whilst limiting subsequent ABPM. This study assessed the cost-effectiveness of using this tool in diagnosing hypertension in Primary Care. A Markov cost-utility cohort model was developed to compare diagnostic strategies: the PROOF-BP approach, including those with clinic BP ≥130/80mmHg who receive ABPM as guided by the algorithm, compared to current standard diagnostic strategies including those with clinic BP ≥140/90mmHg combined with further monitoring (ABPM as reference, clinic and home monitoring also assessed). The model adopted a lifetime horizon with a three month time-cycle, taking a UK Health Service/Personal Social Services perspective. The PROOF-BP algorithm was cost-effective in screening all patients with clinic BP ≥130/80mmHg compared to current strategies which only screen those with clinic BP ≥140/90mmHg, provided healthcare providers were willing to pay up to £20,000 ($26,000)/quality-adjusted life year gained. Deterministic and probabilistic sensitivity analyses supported the base-case findings. The PROOF-BP algorithm appears to be cost-effective compared to the conventional BP diagnostic options in Primary Care. Its use in clinical practice is likely to lead to reduced cardiovascular disease, death and disability.