Objective: The aim of the present study was to evaluate the agreement, mean difference, prevalence, and control rates of arterial hypertension between clinic (i.e. office) and home blood pressure (BP) measurements in a general population. Variations in home BP between morning and evening measurements and the dynamic changes during 7 days of measurements were also examined.
Methods: A total of 200 participants were selected from three communities in the Beijing area. Patients underwent a clinical interview and measurement of both clinic and home BP. Thresholds for elevated clinic and home BP were defined as at least 140/90 and 135/85 mmHg.
Results: Systolic and diastolic BP measured at clinic was higher than at home; the mean difference was 3.1/1.6 mmHg in all participants and 6.2/1.1 mmHg in hypertensive patients. With home BP monitoring, the first day of monitoring showed the highest and most varied (as reflected by standard deviation) BP readings. Home diastolic BP was significantly higher in the morning (76.6 ± 10.1 mmHg) than in the evening (74.2 ± 9.8 mmHg, P<0.0001), but home systolic BP was not. The prevalence of hypertension was higher when estimated by clinic versus by home BP (53.0 vs. 39.6%, P=0.025); and the control rate of hypertension tended to be lower when estimated by clinic versus by home BP (56.1 vs. 64.1%, P=0.24). The overall agreement between clinic and home BP in diagnosis of hypertension was 80.3% (κ coefficient: 0.6).
Conclusion: The present study in 200 Chinese demonstrates that BP is higher (a) at the clinic setting compared with at home and (b) on the first day of initiating home BP monitoring. There is moderate agreement between clinic and home BP in diagnosing hypertension. As home BP measurements may best represent the 'true' BP level in normotensives and hypertensives, its use in clinical practice should be promoted.