Ambulatory blood pressure: associations with coronary heart disease in the aged Finnish population

Background and aims: Ambulatory blood pressure (ABP) has been shown to be a better predictor of cardiovascular events than clinical blood pressure (BP) in middle-aged and older populations. This study studied the association of various components of ABP (daytime, night-time, 24-hour ABP) in the presence of coronary heart disease (CHD) in an older Finnish population. Methods: This cross-sectional, observational, population-based study was carried out in The Lieto Health Centre, Finland, in 1998–99. The study population consisted of 502 subjects (237 men, 265 women) aged 64–87 years. ABP measurements for 24 hours, daytime (awake) and night-time (asleep), were made. Resting electrocardiograms (ECG) were recorded. A person was considered to have CHD if at least one of the following criteria was met: (I) history of coronary by-pass surgery or coronary angioplasty, (II) diagnosis of CHD in previous medical records, (III) ischemia-related changes on ECG. Results: CHD increased by 30% with a 10 mmHg increase in night-time systolic blood pressure (SBP) (OR 1.30, 95% CI 1.15–1.47). When ambulatory 24-hour and daytime SBP values were each entered separately into the multivariate model, 24-hour SBP, but not daytime SBP, was associated with CHD. Conclusions: The most important information gained from 24-h BP monitoring in subjects with CHD is night-time BP. Night-time BP may provide new information about the CHD risk which is not identified in common clinical diagnoses of hypertension. ABP measurements should be made to confirm sufficient control of night-time BP, especially SBP, in older people with CHD.