Recovery Time after Hemodialysis Is Inversely Associated with the Ultrafiltration Rate

Introduction: The present study aimed to determine the variables that are associated with a longer dialysis recovery time (DRT) and to define the relationship that exists between DRT and the ultrafiltration rate (UFR) in prevalent chronic hemodialysis (CHD) patients. Methods: We studied 210 prevalent CHD of 5 hemodialysis units in Central Italy. Patients were invited to answer to the question: “How long does it take you to recover from a dialysis session?” Answers to this question were subsequently converted into minutes. Demographic, clinical and laboratory parameters were recorded for each patient as well as the UFR (mL/kg/h), the dialysate sodium concentration and temperature. Results: Median DRT was 180 min (60–420). Ninety five (45%) patients had a DRT ≥ the median value. Mean UFR was 9.2 ± 3.0 mL/kg/h. Patients with a lower DRT had a less prevalent disability in the instrumental activities daily living, had a higher UFR, and a lower dialysate temperature, as compared with subjects with higher DRT. According to the logistic regression model, UFR was associated with a DRT below the median (i.e., 180) in the unadjusted model (OR 1.12; 95% CI 1.02–1.23; p = 0.019), after adjusting for age and sex (OR 1.11; 95% CI 1.01– 1.22; p = 0.025), and in the fully adjusted model (OR 1.11; 95% CI 1.04–1.22; p = 0.040). UFR increase was associated with increasing probability of DRT below the median (p for trend= 0.035). The highest tertile of DRT was associated with UFR below the mean value (i.e., 9.2 mL/kg/h) in multinomial logistic regression having the lowest DRT tertile as reference. DRT was significantly lower in patients with UFR >13 mL/ kg/h than in patients with UFR 10–13 or <10 mL/kg/h. Conclusion: DRT is inversely associated with UFR in CHD patients. Whether a high UFR should be recommended to reduce the DRT needs to be elucidated through an adequate prospective randomized study.