Blood pressure (BP) levels have tendency to seasonal (winter [W] vs. summer [S]) variability but some aspects of this problem are not studied yet. The aim of our study was to evaluate seasonal and monthly variability of clinical and ambulatory BP (ABP) in patients with arterial hypertension (AH) and high normal BP (HNBP) in S and W in two regions of the Russian Federation with different climate.Design and method:
We included patients from the general population who visited ambulatory clinics in Ivanovo (I) and Saratov (S) for various reasons. The main inclusion criteria were clinical BP (CBP) <160/100 mmHg without or on regular antihypertensive drugs intake (ADI) or CBP = 130/85–139/89 mmHg without ADI. The CBP measurements was performed by automatic tonometer (OMRON 705 IT). The ABP monitoring (ABPM) was performed with the BPLab device (Nizny Novgorod, Russia) twice in each patient: in W (Dec-Feb 2012–2014) and in S (Jun-Aug 2012–2014). The interval between ABPMs was 6 months ± 10 days. The selection criteria for ABPM records were the quality adequate for sophisticated analyses: duration >24 h, absence of data gaps >1 h, >55 readings per 24 h.Results:
In total, 1630 patients were included: 720 in I and 910 in S. The patients of I (the region with lower average ambient temperature compared to S) had higher mean systolic CBP (CSBP) in W than in S (134.4 ± 13.2 mmHg and 129.7 ± 12.6 mmHg, respectively, p < 0.0001). The CSBP in patients of S was also higher in W (128.9 ± 14.3 mmHg) than in S (125.0 ± 16.0 mmHg, p < 0.0001). Monthly averages of CBP/ABP and ambient temperature were not related in S and W.Conclusions:
The seasonal variability of CBP/ABP parameters in patients with AH and HNBP corresponds to the general trend - BP is higher in W than in S. The ambient temperature is not influence on CBP/ABP of patients from two investigated cohort.