Seasonal variation in predialysis systolic blood pressure and cardiovascular events in patients on maintenance hemodialysis.

Predialysis systolic blood pressure (SBP) in patients on hemodialysis (HD) consistently followed a seasonal pattern, reaching a peak in winter and nadir in summer, similar to blood pressure in the general population. However, the relationship between seasonal variations in predialysis SBP and clinical outcomes is still under-investigated in Japanese patients on HD. This retrospective cohort study included 307 Japanese patients undergoing HD for >1 year in three dialysis clinics and evaluated the association between the standard deviation (SD) of predialysis SBP and clinical outcomes, including major adverse cardiovascular events (MACEs; cardiovascular death, nonfatal myocardial infarction or unstable angina, stroke, heart failure, and other severe cardiovascular events requiring hospitalization) with 2.5 years follow-up. The SD of predialysis SBP was 8.2 (6.4-10.9) mmHg. In the model fully adjusted for the SD of predialysis SBP, predialysis SBP, age, sex, HD vintage, Charlson comorbidity index, ultrafiltration rate, renin-angiotensin system inhibitors, corrected calcium, phosphorus, human atrial natriuretic peptide, C-reactive protein, albumin, hemoglobin, body mass index, normalized protein catabolism rate, and intradialytic SBP decline, Cox regression analyses showed that a higher SD of predialysis SBP (per 10 mmHg) was significantly associated with increased MACE risk (hazard ratio [HR], 1.89; 95% confidence interval [95% CI], 1.07-3.36) and all-cause hospitalization (HR, 1.57; 95% CI, 1.07-2.30). Therefore, greater seasonal variations in predialysis SBP were associated with worse clinical outcomes, including MACEs and all-cause hospitalization. Whether interventions to reduce seasonal variations in predialysis SBP will improve the prognosis of Japanese patients on HD must be investigated further.