MON-149 SEASONAL AND WEEKLY VARIABILITY OF BLOOD PRESSURE IN HEMODIALYSIS PATIENTS IN MULTICENTER OF VARIOUS DISTRICT IN JAPAN

Abstract

In general population, there are weekly and seasonal variabilities of blood pressure (BP) which are supposed to be the risk of cardiovascular disease. Home BP is well correlated to the cardiovascular risk compared to office BP. The aims of this study are to determine whether home BP in large number of hemodialysis (HD) patients fluctuate seasonally and weekly and whether the seasonal BP variability correlate to the temperature. 169 dialysis patients (93 male, 76 female) in ten Saiseikai hospitals in various districts in Japan were recruited. All patients were asked to measure BP at least twice a day in a sitting position, once in the morning after urination before breakfast and medication and once in the evening just before going to bed. Data from Oct. 2015 to Oct. 2017 were analyzed. If the dialysis were performed 3 times a week (Mon, Wed, Fri), Monday was defined as 1st day. If the dialysis were performed on Tue. Thurs. and Sat., Tuesday was defined as 1st day. Seasonal variabilities in morning home BP of 1st day and night home BP of 5th day were evaluated. Seasonal changes in clinic BP just before and after HD were also evaluated in 61 patients. Weekly home BP variability in the morning, 1st day 153±16 / 78±13 mmHg, 2nd day 144±28 / 76±12, 3rd day 150±14 / 77±13, 4th day 142±26 / 75±13, 5th day 149±14 / 77±12, 6th day 144±24 / 76±13, 7th day 149±16 / 78±13. Systolic home BPs in 1st, 3rd and 5th days were significantly elevated compared with 2nd, 4th and 6th days. Morning home BP significantly elevated gradually from 6th, 7th and to 1st day. Lowest SBP in the morning was 4th day but not 6th day which was the same as the previous result (CJASN 3: 416-422, 2008). Seasonal variability of morning home BP in 1st day was evident with the rise in autumn and winter (spring 153±19 / 78±12, summer 146±17 / 77±12, autumn 158±16* / 80±12, winter 156±19* / 80±13, * p<0.05 vs summer) (figure). Seasonal changes of highest temperature were significant (spring 19.9±3.1*℃, summer 30.9±2.6, autumn 23.3±2.7*, winter 8.5±2.8*, *p<0.05 vs summer) (figure). Morning BP of 1st day in a randomly selected patient was correlated with highest temperature (r=-0.397、p<0.0001). Seasonal changes of night home BP in 5th day were not significant through four seasons. Seasonal changes in clinic BP just before and after HD, in 1st day before HD: spring 147±19 / 74±13 mmHg, summer 144±20 / 71±11, autumn 150±19 / 74±13, winter 147±21 / 74±12. Systolic BP in autumn was significantly elevated compared to summer. In the other clinic BPs before and after HD in 3rd and 5th days, there were no significant seasonal changes observed. Even in the large number of HD patients, there is weekly home BP variability probably due to volume status. Seasonal morning BP variability was evident in the 1st day of the HD week, but this seasonal home BP variability was disappeared measuring BP in the night without volume overload.