Effect of Ultrafiltration Rate in Long Interdialytic Interval Hemodialysis Session versus Average Weekly Ultrafiltration Rate on Mortality Rate and Adverse Cardiovascular Outcomes in Maintenance Hemodialysis Patients

Objective: Cardiovascular events are more commonly observed during hemodialysis sessions after a long interdialytic interval compared to average weekly hemodialysis sessions, and ultrafiltration rate (UFR) was reported to be associated with cardiovascular outcomes. Whether the UFR during hemodialysis sessions after a long interdialytic interval is a better predictor of cardiovascular outcome than the average weekly UFR is unknown. Methods: The charts of patients aged >18 years with end-stage renal disease that received hemodialysis treatment Siriraj Hospital during January 2008 to December 2017 were retrospectively reviewed. Results: Two hundred and forty-one patients (52.8% females) were included. During the median time follow-up of 54 months, the rate of adverse cardiovascular outcomes was 7.26 events/100-patient-years, and the mortality rate was 8.40 deaths/100-patient-years. Mean UFR was significantly higher in the long interdialytic interval hemodialysis sessions than in the average weekly UFR sessions (14.07±5.29 vs.13.13±5.14 ml/h/kg, p13 ml/hour/kg subgroup was 1.29 (95% CI: 0.65-2.56) and 1.05 (95% CI: 0.55-2.03) in the long interdialytic interval hemodialysis sessions and the average weekly UFR, respectively. The adjusted HR for adverse cardiovascular outcome in the UFR >13 ml/h/kg subgroup was 1.32 (95% CI: 0.64-2.80) and 0.72 (95% CI: 0.36-1.35) in the long interdialytic interval hemodialysis sessions and the average weekly UFR, respectively. Conclusion: This study revealed the UFR in long interdialytic hemodialysis sessions to be more strongly associated with adverse cardiovascular outcomes and all-cause mortality than the average weekly UFR