LAUSR

Objectives: Data is limited regarding the seasonal and regional difference of blood pressure (BP) levels in practice outpatients. We evaluated the seasonal and regional differences of morning home BP. Methods: We used the data of the J-HOP study (Japan Morning Surge-Home Blood Pressure study) which was an observational study evaluating home BP to predict cardiovascular events in outpatients. We measured morning home BP for 14 consecutive days in 67 facilities in various areas of Japan and also calculated day-by-day BP variability parameters such as coefficient variation (CV) and average real variability (ARV). The regions were divided into three areas based on the annual mean temperature of each facility as follows: cold area, < 13°C; intermediate area, 13–15°C; and warm area, ≥15°C. Results: We evaluated 4,102 participants (mean age ± SD, 64.9 ± 10.9 years; 53.0% women; 78.8% taking antihypertensive medication) in this study. In whole area, mean morning systolic blood pressure (SBP) decreased in summer compared to other seasons, without significant differences among other three seasons (Table). Even when analyzing in three areas separately, the results were similar. The CV and ARV of morning SBP also decreased in summer. Regarding the regional difference, the CV and ARV of morning SBP increased in cold area compared to other areas (Table). Conclusion: In Japanese practice outpatients, morning BP level and day-by-day BP variability decreased in summer and increased in cold area. We should pay attention to these seasonal and regional differences in morning BP levels and their day-by-day BP variabilities when we evaluate the hypertensive cardiovascular risk.