Predictive value of ambulatory blood pressure shortly after withdrawal of antihypertensive drugs in primary care patients.

Objective: To determine whether ambulatory blood pressure eight weeks after withdrawal of antihypertensive medication is a more sensitive measure than seated blood pressure to predict blood pressure in the long term.

Design: Patients with previously untreated diastolic hypertension were treated with antihypertensive drugs for one year; these were withdrawn in patients with well controlled blood pressure, who were then followed for one year.

Setting: Primary care.

Subjects: 29 patients fulfilling the criteria for withdrawal of antihypertensive drugs.

Main Outcome Measures: Sensitivity, specificity, and positive and negative predictive value of seated and ambulatory blood pressure eight weeks after withdrawal of antihypertensive drugs.

Results: Eight weeks after withdrawal of medication, mean diastolic blood pressure returned to the pretreatment level on ambulatory measurements but not on seated measurements. One year after withdrawal of medication, mean diastolic blood pressure had returned to the pretreatment level both for seated and ambulatory blood pressure. For ambulatory blood pressure, the sensitivity and the positive predictive value eight weeks after withdrawal of medication were superior to those for seated blood pressure; specificity and negative predictive value were comparable for both types of measurement. Receiver operating characteristic curves showed that the results were not dependent on the cut off values that were used.

Conclusion: Ambulatory blood pressure eight weeks after withdrawal of antihypertensive drugs predicts long term blood pressure better than measurements made when the patient is seated.