Ps-c18-5: seasonal variation in predialysis systolic blood pressure and cardiovascular events in japanese maintenance hemodialysis patients

Objective: Predialysis systolic blood pressure (SBP) in hemodialysis (HD) patients follows a seasonal pattern, peaking during the winter and declining in summer due to changes in ambient temperatures. However, the relationship between seasonal variation in predialysis SBP and clinical outcomes has rarely been studied. We evaluate the association between the seasonal variation in predialysis SBP and clinical outcomes, such as major adverse cardiovascular events (MACEs), in Japanese HD patients. Design and method: In this retrospective cohort study, the standard deviation (SD) of each patient's monthly mean predialysis SBP was determined using the data from 47,219 HD sessions in 307 patients over a year (April 2019 to March 2020) at three dialysis clinics, which was defined as the seasonal variation in predialysis SBP. From April 2020 to March 2022, the relationship between seasonal variation in predialysis SBP and clinical outcomes, including MACEs, was investigated. Cardiovascular death, nonfatal myocardial infarction or unstable angina, stroke, heart failure, and other severe cardiovascular events requiring hospitalization were considered examples of MACEs. Results: The study included 105 women (34%), with an average age and a median HD vintage of 69.0 ± 12.4 years and 4.1 (2.0–7.7) years, respectively. The monthly mean SBP before dialysis was 8.9 ± 3.6 mmHg. There were 77 MACEs (25%) and 184 all-cause hospitalizations (60%) in this study. A Cox regression analysis adjusted for age, sex, HD duration, Charlson comorbidity index, mean annual predialysis SBP, intradialytic SBP decline, and ultrafiltration rate, revealed that a higher SD of the monthly mean predialysis SBP was significantly associated with an increased risk of MACEs (hazard ratio [HR], 1.09; 95% confidence interval [CI], 1.03–1.16). Furthermore, a higher monthly mean predialysis SBP SD was linked to a higher risk of all-cause hospitalization (HR, 1.05; 95% CI, 1.01–1.10). A greater seasonal variation in predialysis SBP was also significantly associated with increased risk of MACEs (HR, 1.08; 95% CI, 1.02–1.16) in the Fine-Gray subdistribution hazards model, considering death and semi-permanent hospitalization due to a decline in Activities of Daily Living as competing risks. Conclusions: A higher seasonal variation in predialysis SBP was linked to poorer clinical outcomes, including an increased risk of MACEs and all-cause hospitalization. More research is needed to confirm whether reducing seasonal variations in predialysis SBP improves this prognosis.