Postdialysis blood pressure is a better predictor of mortality than predialysis blood pressure in Japanese hemodialysis patients: the Japan Dialysis Outcomes and Practice Patterns Study

Abstract

Blood pressure (BP) is reportedly a predictor of mortality in hemodialysis (HD) patients; however, it is unclear whether pre- or postdialysis BP has greater predictive power. To evaluate the association of pre- and postdialysis BP with patient survival in Japanese HD patients, we enrolled the entire phase 3 and 4 Japan Dialysis Outcomes and Practice Patterns Study populations. Among 3176 patients, 486 were excluded because of missing data. The remaining 2690 patients were divided into five groups according to pre- or postdialysis systolic BP (SBP): <100, 100-119, 120-139, 140-159, and ≥160 mmHg; diastolic BP (DBP): <60, 60-79, 80-89, 90-99, and ≥100 mmHg; or pulse pressure (PP): <50, 50-59, 60-69, 70-79, and ≥80 mmHg. The hazard ratios for all-cause and cardiovascular mortalities were estimated according to pre- and postdialysis SBP, DBP, and PP using a Cox proportional hazards model. During the follow-up period, 495 and 193 subjects died because of any cause and cardiovascular disease (CVD), respectively. In the multivariable-adjusted Cox proportional hazards model, U-shaped associations of postdialysis SBP and PP with mortality rates were observed, but no significant associations were observed with predialysis SBP or PP. A stratified analysis showed significant interactions between history of CVD and postdialysis SBP with all-cause and cardiovascular mortality. Compared with predialysis values, postdialysis SBP and PP are better predictors of all-cause and cardiovascular mortality, showing U-shaped associations with these outcomes in Japanese HD patients.

Keywords: All-cause mortality; Cardiovascular death; Hemodialysis; Postdialysis blood pressure; Pulse pressure.