Associations between home blood pressure and mortality in peritoneal dialysis

Objective To investigate the association between the home blood pressure (BP) and morality in peritoneal dialysis (PD). Methods PD patients from the First Affiliated Hospital of Zhejiang University from January 1, 2008 to June 30, 2016 were studied. Over the first 6 months PD therapy, systolic SB (SBP) and diastolic BP (DBP) averaged as 5 (＜120 to≥150 mmHg in 10 mmHg increments) and 4 (＜70 to≥90 mmHg in 10 mmHg increments) categories, respectively, as well as continuous measures. All-cause and cardiovascular mortality were assessed by using Cox regression models adjusted for demographics, laboratory measurements, comorbid conditions and antihypertensive medications. The relationships between home BP and all-cause and cardiovascular mortality were assessed by restricted cubic spline regression model. Results A total of 1663 PD patients were included with a median follow-up of 29.9 months, in which 737 patients (44.3%) were female. The SBP and DBP were (135.2±15.8) mmHg and (83.1±10.5) mmHg, respectively. Two hundred and twenty-one PD patients died during the study period, of which 102 patients (46.2%) died of cardiac-cerebral vascular events. With 130≤SBP＜140 mmHg as a refernece, SBP≥150 mmHg (HR=1.83, 95%CI 1.19-2.82, P=0.005) and SBP＜120 mmHg (HR=2.05, 95%CI 1.29-3.27, P＜0.001) were associated with significantly higher risks of all-cause morality, but not cardiovascular morality. With 80≤DBP＜90 mmHg as a refernece, patients with DBP≥90 mmHg exhibited significantly higher risks of all-cause mortality (HR=1.80, 95%CI 1.21-2.68, P=0.009). SBP presented a U-shaped association with all-cause mortality. DBP presented a J-shaped association with all-cause mortality. Conclusions Higher SBP, lower SBP and higher DBP are associated with higher risks of all-cause mortality in PD patients. However, neither SBP nor DBP is observed statistically significant relationship with the risk of cardiovascular mortality. Further prospective and randomized clinical trials are needed to determine the optimal BP targets and improve the management of hypertension in PD patients.