Reliability of morning, before-dinner, and at-bedtime home blood pressure measurements in patients with hypertension.

The authors evaluated differences in the reliability of home blood pressure measurements taken in the morning, before dinner, and at bedtime. Forty-eight patients with hypertension (age range, 50-89 years; mean age, 76.4 years) measured their home blood pressure using a validated automatic information/communication technology-based device for 14 consecutive days. Those days were divided into the first seven days (1-7) and the following 8 to 14 days (days 8-14) and compared systolic blood pressure (SBP) reliability in the two periods for each measurement time point. In Bland-Altman analyses, morning SBP showed the least standard error of measurement (3.0 mm Hg). There were fixed biases in morning and before-dinner SBP with average limits of agreement of 3.9 and 6.4 mm Hg, respectively. For at-bedtime SBP, a random error was detected and the minimal detectable change was 13.8 mm Hg. The percentage of near-maximal variation of morning SBP was the smallest at 18.1%. Morning SBP therefore provided the most reliable home blood pressure value in the day.