Clinical question: For critically ill patients with acute kidney injury, does early initiation of renal replacement therapy improve mortality?
Bottom line: In this single-center study, early initiation of renal replacement therapy (RRT) in critically ill patients with acute kidney injury (AKI) decreased the number of deaths at 90 days. Larger studies are required to confirm this finding. Although some patients may prefer to avoid dialysis and its inherent risks, this preference must be balanced with the greater risk of mortality that may occur by not undergoing this treatment early on. (LOE = 1b)
Reference: Zarbock A, Kellum JA, Schmidt C, et al. Effect of early vs delayed initiation of renal replacement therapy on mortality in critically ill patients with acute kidney injury. JAMA 2016;315(20):2190–2199.
Study design: Randomized controlled trial (nonblinded)
Funding source: Foundation
Setting: Inpatient (ICU only)
To study the optimal time for initiation of RRT for critically ill patients with AKI, these authors recruited patients with severe sepsis, pressor requirements, refractory fluid overload, or nonrenal organ dysfunction who developed stage 2 AKI (urine output < 0.5 mL/kg/h for more than 12 hours or a 2-fold increase in serum creatinine from baseline). Patients with chronic kidney disease, glomerulonephritis, interstitial nephritis, vasculitis, and postrenal obstruction were excluded, among others.
Overall, 231 patients were randomized to receive either early RRT or delayed RRT. RRT was delivered initially as continuous venovenous hemodiafiltration and could be changed to an intermittent procedure such as intermittent hemodialysis or sustained low-efficiency daily dialysis if renal recovery did not occur after 7 days. Early RRT was initiated within 8 hours of diagnosis of stage 2 AKI while delayed RRT was initiated within 12 hours after patients had developed stage 3 AKI (urine output < 0.3mL/kg/h for more than 24 hours or a 3-fold increase in serum creatinine from baseline) or if patients had an absolute indication for RRT. Patients in the 2 groups had similar baseline Sequential Organ Failure Assessment scores and almost all were surgical patients. Although all patients in the early group received RRT, 9% of patients in the delayed group did not, mostly because they did not progress to stage 3 AKI.
Early RRT resulted in a significantly decreased 90-day mortality rate as compared with delayed RRT (39% vs 55%; P = .03). Patients in the early group also had a decreased duration of RRT (9 days vs 25 days; P = .04), decreased length of hospital stay (51 days vs 82 days; P < .001), and greater recovery of renal function at 90 days (54% vs 39%; P = .02). The authors postulate that initiating early RRT may prevent further injury to the kidneys and other organs by reducing systemic inflammation.
Dr. Kulkarni is an assistant professor of hospital medicine at Northwestern University in Chicago.