Role of ambulatory blood pressure monitoring in the assessment and prognosis of patients with borderline hypertension

The role of ambulatory blood pressure (ABP) monitoring in the assessment of mild/borderline hypertension (BHT) is unclear. The aim of this study was t o test the hypothesis that measurement of ABP in borderline hypertensives d ifferentiates patients with true mild hypertension from those with isolated clinic hypertension (raised office BP but normal ABP) and that a raised AB P identifies a subgroup who are more likely to progress to and require trea tment over 1 year. Consecutive untreated patients with BHT (n = 127, 44 +/- 13 years, 45% male) were divided into two groups according to awake ABP: G roup 1 (normal ABP less than or equal to 136/86, n = 48), and Group 2 (abno rmal ABP > 136/86, n = 79). Left ventricular mass index (LVMI) was greater (116 +/- 30 vs 101 +/- 25g/m(2), p < 0.01) and the proportion of patients w ith an increased LVMI was significantly higher (34% vs 17%, p = 0.05) in Gr oup 2. During 1 year of follow-up, significantly more patients in Group 2 ( 34%) required antihypertensive treatment compared with Group 1 (8%, p = 0.0 1). ABP monitoring usefully discriminates between patients with true BHT an d those with isolated clinic hypertension. An elevated awake ABP on initial assessment is associated with a higher LVMI and a greater likelihood of pr ogression to moderate hypertension requiring pharmacological treatment.