Background: Little is known about isolated ambulatory hypertension, a state with elevated ambulatory but normal office blood pressure (BP). This study aimed to investigate the prognostic significance of isolated ambulatory hypertension for cardiovascular morbidity in a population of elderly men.
Methods and results: At baseline, 24-hour ambulatory BP and metabolic and cardiac risk profiles were evaluated in 578 untreated 70-year-old men, participants of a population-based cohort. Subjects with isolated ambulatory hypertension (office BP <140/90 and daytime BP > or =135/85) and sustained hypertension (office BP > or =140/90 and daytime BP > or =135/85) had increased plasma glucose, body mass index, and echocardiographically determined left ventricular relative wall thickness compared with normotensive subjects (office BP <140/90 and daytime BP <135/85). Seventy-two cardiovascular morbid events (2.37 per 100 person-years at risk) occurred over 8.4 years of follow-up. The prognostic value of isolated ambulatory and sustained hypertension was assessed with Cox proportional hazard regression. Multivariate models adjusting for serum cholesterol, smoking, and diabetes demonstrated that both isolated ambulatory hypertension (hazard ratio [HR], 2.77; 95% CI, 1.15 to 6.68) and sustained hypertension (HR, 2.94; 95% CI, 1.49 to 5.82) were independent predictors of cardiovascular morbidity. In a multivariate model with continuous BP variables, ambulatory daytime systolic BP (HR for 1 SD increase, 1.47; 95% CI, 1.09 to 1.97) was associated with an adverse outcome independently of office systolic BP.
Conclusions: In the present study, isolated ambulatory hypertension as well as sustained hypertension predicted cardiovascular morbidity. The findings suggest that 24-hour ambulatory BP monitoring may disclose important prognostic information also in subjects characterized as normotensive according to office BP.