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

Abstract

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.

Winter morning surge in blood pressure after the Great East Japan Earthquake

“…28 Another study conducted in Japan also demonstrated that the maximum-minimum difference of home morning SBP in a year was +6.7 mmHg (the maximum BP was observed in January and the minimum BP in July). 7 Our results confirmed these earlier results that morning SBP was higher in winter than in summer.…”

“…Compared to young patients, elderly patients show large seasonal BP variations. 3,7,15 This is why elderly patients often have impaired autonomic nervous systems, which results in BP fluctuation. [11][12][13][14] In addition, external factors such as old age of homes and absence of air conditioning, which are often seen in occupant-owned homes of the elderly, might also affect winter BP surge.…”

“…The quality of life in such housing may affect the health of evacuees, since temporary housing tends to be simpler, less spacious, and less comfortable than occupant-owned housing.Blood pressure (BP), including 24-hour ambulatory BP, fluctuates with the seasons and is generally higher in winter and lower in summer. [1][2][3][4][5][6][7] Previous studies have also demonstrated that seasonal BP variations are more highly associated with indoor temperature than outdoor temperature 8,9 and that indoor temperature is mainly determined by the temperature or permanent nature of residential housing. 4,10 Therefore, housing conditions may be one of the greatest determinants of the seasonal BP variations.…”

Variability in Predialysis Systolic Blood Pressure and Long-Term Outcomes in Hemodialysis Patients

“…However, these studies used blood pressure measurements obtained during a period consisting of a consecutive 3 months or less to determine BPV. Because we know that blood pressure fluctuates with season changes [18, 19] and our study also shows that BPV measurements produce different results when obtained over 3 months than when obtained over 12 months, we used a consecutive 12 months of predialysis blood pressure measurements to determine BPV. Tozawa et al [13] also investigated predialysis SBPCV over a 1-year period to predict prognoses in hemodialysis patients, but they did not find an association between BPV and cardiovascular mortality because their follow-up period was short (38 months).…”

The influence of the ambient temperature on blood pressure and how it will affect the epidemiology of hypertension in Asia

“…The results showed that the highest home BP occurred mid to late January, and the differences between the maximum and minimum home SBP and DBP were 6.7 mm Hg and 2.9 mm Hg, respectively. Furthermore, a lower body mass index, older age, and male sex were independently associated with seasonal variation in the home BP …”