Pulse pressure and risk of total mortality and cardiovascular events in patients on chronic hemodialysis

Abstract

Pulse pressure (PP) has been shown as a risk factor for mortality or cardiovascular events in several studies. However, the impact of PP on prognosis in a cohort of chronic hemodialysis patients has not been sufficiently studied. We examined the effect of PP on total mortality and cardiovascular events in chronic hemodialysis patients, and whether PP adds useful value to systolic blood pressure (SBP) or diastolic blood pressure (DBP) for predicting total mortality and cardiovascular events in chronic hemodialysis patients. Chronic hemodialysis patients (N=1243, 720 men, 523 women) alive on January 1, 1991 at baseline were involved in this study. Cox regression, adjusted for age, sex, and other risk factors, was used to assess the relation between blood pressure components and risk of death and cardiovascular events over a nine-year follow-up. The association with the risk of total mortality was positive for PP (P=0.002) and SBP (P=0.04), but not significant for DBP (P=0.4), considering each pressure individually (single blood pressure component model, SPM); of the three measurements, PP yielded the highest chi2 value. When SBP and DBP were jointly entered into the Cox regression model (dual blood pressure component model, DPM), the association with the risk of total mortality was positive for SBP (HR, 1.083; 95% CI, 1.030 to 1.137) and negative for DBP (HR, 0.886; 0.808 to 0.970). After the addition of diabetes mellitus as an adjusted variable to the model, PP was not a significant predictor for total mortality; PP was a significant predictor for total mortality in non-diabetic patients, but not in diabetic patients. PP was positively associated with the risk of stroke, and stroke and AMI; however, predictive value of PP for each endpoint was not superior to SBP and DBP in SPM. In DPM with SBP and DBP, the association with the risk of stroke and acute myocardial infarction (AMI) was positive for SBP (P=0.02) but not significant for DBP (P=0.5). In DPM with SBP and PP, the association with the risk of stroke and AMI was positive for SBP (P=0.01) but not significant for PP (P=0.5). In non-diabetic patients on chronic hemodialysis, PP was an independent predictor of total mortality. PP was more potent predictor of total mortality than SBP or DBP. For predicting cardiovascular events, SBP was superior to PP or DBP.