Seasonal variation in home blood pressure and its relationship with room temperature in patients with type 2 diabetes.

Our aim was to examine the seasonal variations in home blood pressure measurements and the relationship of ambient temperature or room temperature with the seasonal variations in home blood pressure measurements using a home blood pressure telemonitoring system in patients with type 2 diabetes. The home blood pressure measurements of 41 patients with type 2 diabetes were self-measured. Patients performed triplicate morning and evening blood pressure measurements at least 5 days per month for 12 consecutive months. The lowest values of both systolic blood pressure and diastolic blood pressure were observed in August (126.3 and 70.4 mmHg, respectively), and the highest systolic and diastolic blood pressure values were observed in January (140.3 and 76.9 mmHg, respectively). The root mean squared error between the mean systolic blood pressure and room temperature was 6.50 mmHg and between mean systolic blood pressure and ambient temperature was 6.55 mmHg. Using a home blood pressure telemonitoring system, this study revealed for the first time that home blood pressure varied seasonally, with the highest values observed in January and the lowest values observed in August, and that the seasonal variations in home blood pressure were related to room temperature as well as ambient temperature.