Audit of ambulatory blood pressure monitoring in the diagnosis and management of hypertension in practice

This study was carried out to ascertain the value of ambulatory blood pressure monitoring (ABPM) in the diagnosis and treatment of hypertension in routine clinical practice. ABPM was performed during the daytime hours in 410 patients believed to be hypertensive after at least three measurements by their physician and one measurement by a nurse in a hypertension clinic. The diagnosis was confirmed in 70% of patients when 90 mm Hg diastolic blood pressure (BP) was used as the upper limit of normal, and 86.3% when 85 mm Hg was used. In 204 patients who were reviewed 5 years later there were 108 on medical treatment. This reduced diastolic pressure from a mean of 100.6 +/- 8.8 to 85.7 +/- 8.8 mm Hg. However, in 30% of patients the diastolic pressure was still above 90 mm Hg. In the 49 patients with isolated clinic hypertension (ICH), who had remained untreated, diastolic pressure increased from 84.0 +/- 4.8 to 88.1 +/- 8.4 mm Hg over the 5 years. In 19 of these the level exceeded 90 mm Hg. ABPM therefore improves diagnostic accuracy and prevents treatment of patients with ICH. This condition, however, requires follow-up since BP tends to rise with time in some patients. The audit also identified patients who had had a suboptimal response to medical treatment.