Journal Article

Seasonal variation in self-measured home blood pressure among patients on antihypertensive medications: HOMED-BP study

Imai, Yutaka, Hanazawa, Tomohiro, Inoue, Ryusuke, Yasui, Daisaku, Ohkubo, Takayoshi, Obara, Taku, Watabe, Daisuke, Hosaka, Miki, Satoh, Michihiro, Metoki, Hirohito, Kikuya, Masahiro, Asayama, Kei

2017

Overview

Seasonal variation of blood pressure (BP) has been reported in small populations or by BP levels captured at only a few points in a year, for example, summer and winter. We aimed to investigate the multiyear seasonal variation in self-measured home BP among hypertensive patients receiving antihypertensive medications. We selected 1649 eligible patients receiving antihypertensive drug treatment, and weekly averaged home BPs were analyzed throughout the follow-up period. Systolic and diastolic home BPs were fitted with the cosine function: 'Variation+Other Effects+Intercept', in which the 'Variation' was expressed by a cosine curve with three parameters representing: (1) maximum-minimum difference of home BP in one cycle of the cosine curve; (2) time required for one cycle of the cosine curve for home BP variation; and (3) time at which home BP reached the maximum point. Maximum-minimum differences in home BP were 6.7/2.9 mm Hg, and the highest home BPs were observed in mid-to-late January. In the multivariable-adjusted model, a large maximum-minimum difference in home BP was associated with lower body mass index and older age, and larger differences were observed in men compared with women. Summer-winter difference in home BP was essentially similar every year, though it was marginally reduced by 0.14/0.04 mm Hg per year, under long-term antihypertensive treatment. Records of daily home BP measurements enable us to capture long-term factors such as seasonal variation. Home BP should therefore be carefully monitored, particularly in patients with increased BP in winter, to mitigate cardiovascular risk.

• Publisher: Nature Publishing Group
• Subject: Aged / Antihypertensive Agents - pharmacology / Antihypertensive Agents - therapeutic use / Antihypertensives / Blood pressure / Blood Pressure - drug effects / Blood Pressure - physiology / Blood Pressure Determination / Female / Home medical tests / Humans / Hypertension / Hypertension - drug therapy / Hypertension - physiopathology / Male / Middle Aged / Pressure measurement / Seasons / Sex Factors