Ambulatory monitoring predicts development of drug-treated hypertension in subjects with high normal blood pressure

Background: High normal blood pressure (HNBP), i.e. blood pressure (BP) greater than or equal to130/85 mmHg and <140/90 mmHg, is an important predictor of progression to established hypertension. Design: The purpose of this retrospective study was the evaluation of the predictive value of ambulatory blood pressure monitoring (ABPM) for the development of drug-treated hypertension in subjects with HNBP and other risk factors. Methods: We studied 127 subjects (69 M, 58 F, age 50 +/- 14 years): 59 subjects had normal BP (NBP: <130/85 mmHg), 68 subjects had systolic and/or diastolic HNBP. All the subjects underwent ABPM. There were 21/68 (30.9%) subjects in the HNBP group vs. 1/59 (1.7%) in the NBP group with an elevated (>135/85 mmHg) daytime ambulatory blood pressure (ABP) (p<0.01). Results: After an average follow-up of 103 +/- 28 months, 27 subjects (39.7%) in the HNBP group and 4 subjects (6.8%) in the NBP group developed drug-treated hypertension (p<0.01). An elevated daytime ABP correctly predicted development of drug-treated hypertension in 17/21 subjects (81%) of the HNBP group and in the only subject of the NBP group. Development of drug-treated hypertension was associated with higher office and ambulatory BP (p<0.01) and pulse pressures (p<0.05), longer follow-up (p<0.05) and higher prevalence of hypercholesterolaemia and smoking(p<0.01). Conclusions: We conclude that ABPM correctly predicts development of drug-treated hypertension in most subjects who were identified early as having a daytime mean ABP >135/85 mmHg. ABPM appears to be a useful clinical tool in the early diagnosis of hypertension in subjects with metabolic risk factors and smoking.