Safe withdrawal of monotherapy for hypertension is poorly effective and not likely to reduce health-care costs

OBJECTIVE: To carry out a population-based evaluation of withdrawal of treatment in primary care using repeated ambulatory blood pressure monitoring (ABPM) assessment to avoid subjecting patients to prolonged periods of excess risk. METHOD: Patients from two community practices (total population 11 034 patients) being administered monotherapy for hypertension, were identified and invited to participate. Subjects were withdrawn from treatment if they had no significant co-morbidity and daytime ABPM blood pressure was < or = 150/90 mmHg. Antihypertensive therapy was restarted if daytime ABPM blood pressure was > 150/90 mmHg during weeks 4, 8, 12, 26, 39 and 52. RESULTS: Of 126 eligible patients 53 had a co-morbidity and 37 declined to participate. Of the 36 patients who entered the study 10 were excluded because they had elevated ABPM blood pressures during treatment and one because they had echocardiographic left ventricular hypertrophy. Of the 25 patients from whom monotherapy was withdrawn, we restarted treatment of 19 before week 52. If clinic blood pressure monitoring had been used instead of ABPM, different decisions would have been taken in eight of 25 cases. The costs of the ABPM-determined withdrawal of treatment programme were greater than the expected savings in drug costs, even assuming that all six patients from whom treatment was withdrawn remained without treatment for a further 9 years. This conclusion was not sensitive to reducing the number of ABPM measurements and to inflation in study-drug costs. However, if all patients had been treated with the most expensive drug, then even the full ABPM programme could have saved money within 9 years. CONCLUSIONS: Antihypertensive therapy could be withdrawn from only a small proportion of patients in the community on the basis of ABPM. The costs of the programme are likely to exceed savings unless the cost of drugs administered is substantially higher than that observed in this study.