Dialysis Discontinuation Rates at Low Levels of Kidney Function in Patients with Acute Kidney Injury on Intermittent Hemodialysis

BACKGROUND: Anticipating when dialysis can be discontinued for patients with acute kidney injury requiring dialysis (AKI-D) is a common, but challenging, clinical problem. While timed urine collection metrics like creatinine clearance and urine output are often proposed to inform the decision, few studies have rigorously quantified the need for ongoing dialysis by level of creatinine clearance, particularly in the period after critical illness has resolved when competing risk of death drops and liberation from dialysis becomes a relatively higher clinical priority. We hypothesized that many patients would not require dialysis even at relatively low levels of residual kidney function (e.g., creatinine clearance below 10 mL/min). METHODS: In this ancillary study of the LIBERATE-D trial intervention arm, timed urine collections blinded to clinicians were performed per protocol, and dialysis was performed for prespecified indications. Logistic regressions computed predicted probabilities of requiring dialysis in the subsequent seven days by level of measured creatinine clearance, urea clearance, the average of creatinine and urea clearances, urine output, and eGFR calculated from the serum creatinine. The fraction of patients requiring dialysis in the subsequent week at various thresholds of creatinine clearance and urine output were also reported. RESULTS: Among 147 timed urine collections from 85 patients with AKI-D, median [IQR] creatinine clearance was 7.1 [3.1-15.9] mL/min and median urine output was 930 [471-1786] mL/day. Creatinine clearance demonstrated significantly higher discrimination (AUC 0.84) than urine output (AUC 0.78). Dialysis was not required in the subsequent week for 81% (22 out of 27) of urine collections with creatinine clearance 10-20 mL/min and 44% (19 out of 43) with creatinine clearance 5-<10 mL/min. CONCLUSIONS: In a clinical trial with protocolized dialysis indications for hemodynamically stable patients with AKI-D, patients with lower levels of kidney function such as creatinine clearance of 5-10 mL/min were often able to discontinue dialysis.