Does renal replacement therapy increase mortality in the ICU?
© BioMed Central Ltd 2011
Published: 24 March 2011
Renal replacement therapy (RRT) is associated with potential risks such as hypotension, catheter-related complications, hemorrhage and blood-extracorporeal circuit interactions. Several studies, however, have shown that early RRT in acute kidney injury (AKI) is associated with a better outcome in intensive care unit (ICU) patients [1–3].
A recent retrospective study published in Critical Care has questioned the use of RRT in critically ill patients, including those with severe AKI . Compared with conservative treatment, RRT patients showed a higher mortality. The indication for RRT was at the discretion of the physician, and patients receiving RRT presented higher severity and renal impairment scores. After multivariate analysis correcting for severity of illness (Acute Physiology and Acute Chronic Health Evaluation II score and Sequential Organ Failure Assessment score), mortality remained higher in RRT patients. In a multivariate analysis in septic shock patients, however, we observed that both severity scores are not related to mortality, contrary to the maximum Sequential Organ Failure Assessment score . The decision of starting RRT in many patients during their ICU stay may have been related to evolving factors not included in the analysis (worsening severity, overload, progressing hypoxemia, and so forth), which affect mortality but are not detected in the initial snapshot assessment. For instance, it is inconceivable that anuric patients did not receive RRT. On the other hand, the use of RRT in some patients with mild renal impairment may have increased morbidity.
The study underlines the idea that RRT is not necessary in many patients presenting mild AKI in the ICU, but may be misleading if we accept that this therapy is deleterious in general.
Monique M Elseviers and Robert L Lins
We appreciate the comments of Dr Pestaña and understand his concerns about a possible misinterpretation of the results by considering our findings in too general a manner.
First, however, we have to rectify that the overall Stuivenberg Hospital Acute Renal Failure results published in this journal did not derive from retrospective observations but from a prospective study of 1,303 AKI patients consecutively admitted to the ICU. Furthermore, disease severity was initially investigated using the Stuivenberg Hospital Acute Renal Failure score . This validated AKI-specific severity scoring system proved to have high performance in comparison with other general and specific severity scores . It was only additionally that we corrected for Acute Physiology and Acute Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, both showing only a limited predictive value for mortality.
We agree with Pestaña that in some of the critically ill AKI patients, the indication to start RRT treatment is clearly established. Recent reviews, however, demonstrated that the available literature remains inconclusive regarding the optimal indications for RRT in AKI patients [8, 9]. Arguably only metabolic acidosis, hypervolemia and hyperkalemia that do not respond to other forms of therapy are absolute indications for initiation of RRT .
In the Stuivenberg Hospital Acute Renal Failure study, we determined RRT as an independent risk factor for mortality. In view of the current lack of evidence for initiating RRT, we tried to formulate our recommendations carefully - stating only that a more critical approach to the need for RRT in AKI patients seems to be warranted, and pleading for an individualized approach in each patient.
acute kidney injury
intensive care unit
renal replacement therapy.
- Ostermann M, Chang RWS: Correlation between parameters at initiation of renal replacement therapy and outcome in patients with acute kidney injury. Crit Care 2009, 13: R175. 10.1186/cc8154PubMed CentralView ArticlePubMedGoogle Scholar
- Bell M, Liljestam E, Granath F, Fryckstedt J, Ekbom A, Martling CR: Optimal follow-up time after continuous renal replacement therapy in actual renal failure patients stratified with the RIFLE criteria. Nephrol Dial Transplant 2005, 20: 354-360. 10.1093/ndt/gfh581View ArticlePubMedGoogle Scholar
- Shiao CC, Wu VC, Li WY, Lin YF, Hu FC, Young GH, Kuo CC, Kao TW, Huang DM, Chen YM, Tsai PR, Lin SL, Chou NK, Lin TH, Yeh YC, Wang CH, Chou A, Ko WJ, Wu KD: Late initiation of renal replacement therapy is associated with worse outcome in acute kidney injury after major abdominal surgery. Crit Care 2009, 13: R171. 10.1186/cc8147PubMed CentralView ArticlePubMedGoogle Scholar
- Elseviers M, Lins RL, Van der Niepen P, Hoste E, Malbrain ML, Damas P, Devriendt J, for the SHARF investigators: Renal replacement therapy is an independent risk factor for mortality in critically ill patients with acute kidney injury. Crit Care 2010, 14: R221. 10.1186/cc9355PubMed CentralView ArticlePubMedGoogle Scholar
- Pestaña D, Espinosa E, Sangüesa-Molina JR, Ramos R, Pérez-Fernández E, Duque M, Martínez-Casanova E: Compliance with a sepsis bundle and its effect on intensive care unit mortality in surgical septic shock patients. J Trauma 2010, 69: 1282-1287.View ArticlePubMedGoogle Scholar
- Lins RL, Elseviers MM, Daelemans R, Arnouts P, Billiouw JM, Couttenye M, Gheuens E, Rogiers P, Rutsaert R, Van der Niepen P, De Broe ME: Reevaluation and modification of the Stuivenberg Hospital Acute Renal Failure (SHARF) scoring system for the prognosis of acute renal failure: an independent multicenter, prospective study. Nephrol Dial Transplant 2004, 19: 2282-2288. 10.1093/ndt/gfh364View ArticlePubMedGoogle Scholar
- Costa e Silva VT, de Castro I, Liaño F, Muriel A, Rodríguez-Palomares JR, Yu L: Sequential evaluation of prognostic models in the early diagnosis of acute kidney injury in the intensive care unit. Kidney Int 2009, 75: 982-986. 10.1038/ki.2009.3View ArticlePubMedGoogle Scholar
- Pannu N, Klarenbach S, Wiebe N, Manns B, Tonelli M, Alberta Kidney Disease Network: Renal replacement therapy in patients with acute renal failure: a systematic review. JAMA 2008, 299: 793-805. 10.1001/jama.299.7.793View ArticlePubMedGoogle Scholar
- Gibney RT, Bagshaw SM, Kutsogiannis DJ, Johnston C: When should renal replacement therapy for acute kidney injury be initiated and discontinued? Blood Purif 2008, 26: 473-484. 10.1159/000157325View ArticlePubMedGoogle Scholar