Ultrafiltration rates and intradialytic hypotension: A case-control sampling of pooled haemodialysis data

Background: Intradialytic hypotension (IDH) is one of the most critical adverse events during maintenance haemodialysis. Previous studies reported the association of fluid removal rate with the occurrence of IDH. Objective: We aimed to identify the optimal threshold of ultrafiltration rate to prevent the occurrence of IDH events. Design, Participants and Measurements: Prognostic factor research with a retrospective case-control design was conducted. Patient data were gathered from four haemodialysis units from January to December 2017. All the haemodialysis records were independently justified, whether IDH occurred or not, based on the standard definition. A total of 10 haemodialysis sessions were sampled from each patient's pool based on the incidence of events. The association of ultrafiltration rates and IDH events was explored by multivariable multilevel logistic regression. Results: A total of 1080 haemodialysis sessions from 108 patients were included: 149 (13.8%) with IDH and 931 (86.2%) without IDH. After adjusting for all pre-specified risk factors and imbalance baselines, the odds ratio of IDH were 1.22 (95% confidence interval [CI]: 0.59, 2.52) for rate 10-12 ml/kg/h; 2.52 (95% CI: 1.20, 5.29) for rate 12-14 ml/kg/h; 4.02 (95% CI: 1.61, 10.03) for rate 14-16 ml/kg/h; and 7.41 (95% CI: 2.53, 21.68) for rate >16 ml/kg/h comparing to the referent rate of <10 ml/kg/h. Conclusion: The ultrafiltration rate should be limited to 12 ml/kg/h. If a higher rate of fluid removal was indicated, it should not exceed 16 ml/kg/h to avoid the occurrence of IDH.