Comparison of nocturnal blood pressure based on home versus ambulatory blood pressure measurement: The Ohasama Study

The nocturnal blood pressure (BP) is a strong predictor of hypertensive target organ damage including that in cardiovascular diseases. The use of ambulatory BP (ABP) monitoring has enabled the evaluation of nocturnal BP and detection of non-dippers. This study compared nocturnal BP values, nocturnal decline in BP, and the prevalence of non-dippers based on ABP and home BP (HBP) measurements in a general population. Data on HBP measured with HEM 747-IC-N (Omron Healthcare Co., Ltd.) and 24-hour ABP measured with ABPM-630 (Nippon Colin) were obtained from fifty-five participants aged ≥ 20 years (mean age: 65.1 years, 78.2% women). To exclude a systematic difference between the two methods, we conducted a validation study for HBP and ABP in another population that consisted of hypertensive outpatients (mean age: 65.4 years, 53.4% women). After adjusting for the systematic difference in BP between the two methods calculated in the validation study (3.9 mmHg for systolic and 3.0 mmHg for diastolic), morning and daytime (average of morning and evening) HBP were significantly lower than morning (average of 2 h after waking) and daytime (average of being awake) ABP, respectively. No significant difference was found in nocturnal BP between HBP and ABP monitoring regardless of the quality of sleep during nocturnal HBP measurement. Agreement between HBP and ABP in the detection of non-dippers was low mainly due to the difference in daytime BP values. Conclusion: HBP monitoring may be a reliable alternative to ABP for the assessment of nocturnal BP.