Estimate of nocturnal blood pressure and detection of non-dippers based on clinical or ambulatory monitoring in the inpatient setting

Background: Ambulatory blood pressure monitoring is regarded as the gold standard for monitoring nocturnal blood pressure (NBP) and is usually performed out of office. Currently, a novel method for monitoring NBP is indispensible in the inpatient setting. The widely used manual BP monitoring procedure has the potential to monitor NBP in the hospital setting. The feasibility and accuracy of manual sphygmomanometer to monitor NBP has not been explored widely. Methods: A cross-sectional study was conducted at the cardiology department of a university-affiliated hospital to study patients with mild-to-moderate essential hypertension. One hundred and fifty-five patients were recruited to compare BP derived from a manual device and ambulatory BP monitoring (ABPM). The manual BP measurement was performed six times at 22: 00, 02: 00, 06: 00, 10: 00, 14: 00 and 18: 00 h. The measurements at 22: 00, 02: 00 and 06: 00 h were defined as night-time and the others as daytime. ABPM was programmed to measure at 30-min intervals between measurements. Results: All-day, daytime and night-time BP did not differ significantly from 24-h ambulatory systolic BP [all-day mean difference -0.52 +/- 4.67 mmHg, 95% confidence interval (CI) -1.26 to 0.22, P= 0.168; daytime mean difference 0.24 +/- 5.45 mmHg, 95% CI -0.62 to 1.11, P= 0.580; night-time mean difference 0.30 +/- 7.22 mmHg, 95% CI -0.84 to 1.45, P= 0.601) rather than diastolic BP. There was a strong correlation between clinical and ambulatory BP for both systolic and diastolic BP. On the basis of ABPM, 101 (65%) patients were classified as non-dippers, compared with 106 (68%) by manual sphygmomanometer (P< 0.001). Conclusions: Traditional manual sphygmomanometer provides similar daytime and night-time systolic BP measurements in hospital. Moreover, the detection of non-dippers by manual methods is in good agreement with 24-h ABPM. Further studies are required to confirm the clinical relevance of these findings by comparing the association of NBP in the hospital ward assessed by manual monitoring with preclinical organ damage and cardiovascular and cerebrovascular outcomes.