Cost analysis of ambulatory blood pressure monitoring in initiating antihypertensive drug treatment in Australian general practice.

OBJECTIVE To compare the cost of ambulatory blood pressure monitoring (ABPM) with the putative savings made through treatment avoided by identification and non-treatment of those with "white coat" hypertension. DESIGN A cost analysis based on a model of four alternative strategies (no ABPM, yearly, two-yearly, or three-yearly monitoring) over a seven-year period applied to a case series from Australian general practice. PARTICIPANTS 62 patients newly diagnosed by their GPs as having hypertension and requiring drug treatment. MAIN OUTCOME MEASURES The proportion of patients shown to not need treatment. The discounted costs to the Pharmaceutical Benefits Scheme, Medical Benefits Scheme and patients. RESULTS 16 of 62 patients (26%; 95% CI, 15%-37%) were normotensive on ABPM and did not require treatment. All monitoring strategies are more expensive in the first year, but the initial costs are offset by year 3 and the monitoring strategies are cost saving thereafter. Sensitivity analysis shows that this result holds across a range of costs of pharmacotherapy and proportion of patients with white coat hypertension. CONCLUSION The additional costs of 24-hour ABPM in the first year are offset by savings associated with patients with white coat hypertension who would otherwise have been treated.