The association between BP and mortality in patients on chronic peritoneal dialysis

Background. The relationship between blood pressure (BP) and mortality in haemodialysis patients is unconventional. It is not clear if this is the consequence of uraemia or related to the dialysis type. The goal of this project was to identify the relationship between BP and mortality in patients on chronic peritoneal dialysis (PD). Methods. Patients on PD (n = 1053) from the USRDS prospective DMMS Wave 2 study were analysed. Primary outcomes were all-cause and cardiovascular mortality and duration of hospitalization. Results. Low systolic BP categories, <100 mmHg [hazard ratio (HR), 2.71, P<0.001; and HR 3.83, P < 0.001, respectively] and 101-110 mmHg (HR 1.85, P<0.05; and HR 2.92, P<0.005, respectively), but not high systolic BP, increased the risk of all-cause and cardiovascular mortality, with systolic BP 111-120 mmHg as the reference. Pulse BP, but not diastolic BP, followed a similar trend. In subgroup analysis, this association was demonstrated only in patients with a history of heart failure, in patients with diabetes and in those treated with antihypertensive medications. Conclusion. Systolic BP <111 mmHg in PD patients is associated with higher mortality risk, while systolic BP >120 mmHg is associated with fewer hospital days. Aggressive treatment of hypertension in the PD population should be cautioned.