Recovery Time after Hemodialysis Is Inversely Associated with the Ultrafiltration Rate

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.

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.

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.

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.