Correlation of repeated measurements of home blood pressure on one occasion and diagnosis of hypertension: study by measurement over seven consecutive days.

In spite of the recent recognition of the usefulness of home blood pressure (BP) measurement, there are no clear guidelines for which measurements should be used for clinical evaluation. Therefore, the present study examined the correlation of repeated measurements of home BP on one occasion and the diagnosis of hypertension (HT) or normotension (NT). Home BP was measured with 700 volunteers aged 20 years or older (468 male and 232 female, mean age 40.6 years) in a sitting position three times each in the morning and evening for seven consecutive days. Excluding the measurements on the first day, the mean values were calculated for the first measurement (group A), second measurement (group B), the mean of the first and second measurements (group C), and the mean of the second and third measurements (group D). The correlation with the frequency of diagnosis of HT (>/=135/85 mmHg) and NT (<125/80 mmHg) was studied. Home BP in the morning and evening were both highest in group A (morning: 122.1 +/-0.6 (SEM)/75.9 +/-0.4 mmHg, evening: 120.4 +/-0.6/71.8 +/-0.4 mmHg) and lowest in group D (morning: 119.5 +/-0.6 / 75.2 +/-0.4 mmHg, evening: 117.5 +/-0.6/70.6 +/-0.4 mmHg). Using morning home BP, HT was diagnosed more often in group A (27.4%) than in group D (24.7%), with a lower frequency of NT diagnosis (55.7% vs. 61.7%; p = 0.06). With regard to the diagnosis made from evening home BP, HT was diagnosed more often and NT was diagnosed less often in group A (HT/NT: 18.4%/61.4%) than in group D (13.7%/68.0%), with statistical significance (p = 0.02). In conclusion, when the clinical diagnosis was made from seven-day home BP, the diagnosis of HT was made more frequently and NT diagnosis was made less frequently using the first measurement than the mean of the second and third measurements. This trend was more pronounced when diagnosis was made from evening home BP.