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Year : 2007  |  Volume : 17  |  Issue : 1  |  Page : 1-3

Improving outcomes from acute kidney injury: Report of an initiative

Acute Kidney Injury Network (AKIN) Working Group, India

Correspondence Address:
A Kirpalani
Professor of Nephrology, University of Mumbai, Bombay Hospital Institute of Medical Sciences, Mumbai
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-4065.35011

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Keywords: Acute kidney injury, acute renal failure, clinical trials, collaboration, conference, consensus, definitions, diagnosis, dialysis, initiative, network, research, staging

How to cite this article:
Kirpalani A, Bagga A, Levin A, Warnock D G, Mehta R L, Kellum J A, Shah S, Molitoris B A, Ronco C. Improving outcomes from acute kidney injury: Report of an initiative. Indian J Nephrol 2007;17:1-3

How to cite this URL:
Kirpalani A, Bagga A, Levin A, Warnock D G, Mehta R L, Kellum J A, Shah S, Molitoris B A, Ronco C. Improving outcomes from acute kidney injury: Report of an initiative. Indian J Nephrol [serial online] 2007 [cited 2022 Dec 2];17:1-3. Available from:

Acute kidney injury (AKI) is a common clinical problem, defined by an abrupt (< 48 h) increase in serum creatinine resulting from an injury or insult that causes a functional or structural change in the kidney. Recent epidemiological studies have demonstrated wide variations in the etiologies and risk factors associated with AKI. [1],[2],[3],[4] The already high in-hospital mortality following AKI further worsens if dialysis is required. [1],[2],[3],[4] There is emerging recognition that even minor short-term changes in serum creatinine are associated with increased mortality; [5],[6],[7],[8],[9] other important consequences of AKI are progression of preexisting chronic kidney disease (CKD) and even development of end-stage renal disease (ESRD). [10],[11],[12]

A major limitation in improving outcomes from AKI has been the lack of common standards for diagnosis and classification. Recognizing that future clinical and translational research in AKI will require the development of multidisciplinary collaborative networks of investigators, a group comprising members from the acute dialysis quality initiative (ADQI) [13] and nephrology and critical care societies recently established the acute kidney injury network (AKIN) [14] in order to facilitate international, interdisciplinary, and intersociety collaboration that will ensure progress in the field of AKI. The fundamental goal is to ensure the best outcomes for patients with, and at risk for, AKI. The first AKIN conference, held in Amsterdam in September 2005, focused on the development of uniform standards for the definition and classification of AKI. While the complete report is published elsewhere, [14] the key elements are summarized in this article.

 ~ Recommendations Top

Proposal for uniform standards for the definition and classification of AKI

Previous studies have used assorted definitions for AKI; including serum creatinine changes, absolute levels of serum creatinine, changes in urine output or blood urea nitrogen, or the need for dialysis. The wide variations in definitions has made it difficult to compare information across studies and populations. [15] The proposed diagnostic criteria for AKI are shown in [Table - 1] and are based on the following considerations:

  1. The definition should be based on readily obtained criteria that are available worldwide and needs to be broad enough to accommodate variations in clinical presentation over different age groups, locations, and clinical situations.
  2. Serum creatinine and urine output are two common measures that reflect renal function; however, they are each influenced by factors other than the glomerular filtration rate and do not provide information on the nature and site of kidney injury.
  3. There is a lack of sensitive and specific markers for kidney injury available in clinical practice at present, although several kidney specific biomarkers are under development. [16]

The absolute criteria for diagnosing AKI are based on the evidence that small changes in serum creatinine are associated with adverse outcomes in a variety of settings. These changes manifest both with short-term increases in morbidity and mortality and with longer-term outcomes, including 1-year mortality. The coefficient of variation of serum creatinine with modern analyzers is relatively small; therefore, changes of ≥0.3 mg/dl are unlikely to be due to assay variation. [19] Urine output was included as a diagnostic criterion because in the ICU it often portends renal dysfunction, before changes in serum creatinine become evident. Urine output was included as a criterion although hydration state, use of diuretics, and the presence of obstruction to urinary flow can all influence the urine volume. A time constraint of 48 h for diagnosis was proposed to ensure that the process was acute and representative of events within a clinically relevant time period.

[Table - 2] shows the proposed staging system for AKI; it is intended to enable definition of the level of renal dysfunction at the time of diagnosis and to allow tracking of the course of the disease over time. The RIFLE criteria [13] utilize changes in serum creatinine and urine output to characterize three levels of renal dysfunction. The proposed staging system for AKI retains the emphasis on changes in serum creatinine and urine output and corresponds to the 'risk,' 'injury,' and 'failure' categories of the RIFLE classification, with the Stage 1 criteria representing the new diagnostic criteria for AKI. The 'loss' and 'ESKD' categories of the RIFLE system were removed from the present staging system as they are outcomes of AKI itself. The proposed diagnostic and staging criteria for AKI are designed to facilitate acquisition of new knowledge in this field and validate the emerging concept that small alterations in kidney function may contribute to adverse outcomes. The Network recognizes that these criteria may be overly sensitive; there may be an increase in false positives, so that some patients labeled with AKI will not have the disease. Further, it is evident that these criteria will require evaluation and validation and, eventually, amendment as new biomarkers emerge that may prove to be better in identifying AKI. [16]

International collaborative network

Establishment of an international collaborative research network could facilitate acquisition of evidence through well-designed and conducted clinical trials, dissemination of information via multidisciplinary joint conferences and publications, and translation of knowledge from preclinical research. The group proposed to further develop the AKIN collaborative effort based on four major principles: 1) identifying the key roles of each of the existing societies/ groups to allow retention of their individual identities and strengths, while leveraging the opportunity for collaboration; 2) defining the scope of the collaboration; 3) ascertaining and developing the infrastructure needed for the collaborative network; and 4) identifying unifying principles and the initial projects that would form the basis of ongoing collaboration. [14]

Future directions

The AKIN conference recognized that collaborative and integrated joint conferences are essential to facilitate the dissemination of knowledge, clarify clinical practice, and enhance research. The group described the five key elements that should be addressed by the professional communities involved in the care of patients with AKI. [14] These include evaluation of the global epidemiology of AKI, delineation of clinically meaningful outcomes, development and implementation of strategies to improve outcomes, promotion of research studies to enhance knowledge, and assessment of the effectiveness of these collaborative approaches. A follow-up conference was held in Vancouver in 2006 and the results are to be published soon.

 ~ Conclusions Top

AKI is a complex disorder caused by several etiological factors and occurring in multiple settings with varied clinical manifestations that may range from a minimal elevation in serum creatinine to anuric renal failure. We have described the formation of a multidisciplinary collaborative network focused on AKI and, within this network, have proposed uniform standards for diagnosing and classifying AKI. While these proposed standards will need to be validated in future studies, the AKIN offers a forum to encourage knowledge acquisition and, thus, improve patient outcomes.

 ~ References Top

1.Mehta RL, Pascual MT, Soroko S, Savage BR, Himmelfarb J, Ikizler TA, et al . Spectrum of acute renal failure in the intensive care unit: the PICARD experience. Kidney Int 2004;66:1613-21.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2.Metnitz PG, Krenn CG, Steltzer H, Lang T, Ploder J, Lenz K, et al . Effect of acute renal failure requiring renal replacement therapy on outcome in critically ill patients. Crit Care Med 2002;30:2051-8.  Back to cited text no. 2  [PUBMED]  [FULLTEXT]
3.Uchino S, Kellum JA, Bellomo R, Doig GS, Morimatsu H, Morgera S, et al . Acute renal failure in critically ill patients: A multinational, multicenter study. JAMA 2005;294:813-8.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]
4.Liangos O, Ron Wald, O'Bell JW. Epidemiology and outcomes of acute renal failure in hospitalized patients: A national survey. Clin J Am Soc Nephrol 2006;1:43-51.  Back to cited text no. 4    
5.Chertow GM, Burdick E, Honour M, Bonventre JV, Bates DW. Acute kidney injury, mortality, length of stay and costs in hospitalized patients. J Am Soc Nephrol 2005;16:3365-70.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]
6.Lassnigg A, Schmidlin D, Mouhieddine M, Bachmann LM, Druml W, Bauer P, et al . Minimal changes of serum creatinine predict prognosis in patients after cardiothoracic surgery: A prospective cohort study. J Am Soc Nephrol 2004;15:1597-605.  Back to cited text no. 6  [PUBMED]  [FULLTEXT]
7.Levy MM, Macias WL, Vincent JL, Russell JA, Silva E, Trzaskoma B, et al . Early changes in organ function predict eventual survival in severe sepsis. Crit Care Med 2005;33:2194-201.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]
8.McCullough PA, Soman SS. Contrast-induced nephropathy. Crit Care Clin 2005;21:261-80.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]
9.Hoste EA, Clermont G, Kersten A, Venkataraman R, Angus DC, De Bacquer D, et al . RIFLE criteria for acute kidney injury is associated with hospital mortality in critically ill patients: A cohort analysis. Crit Care 2006;10:R73.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]
10.Druml W. Long term prognosis of patients with acute renal failure: Is intensive care worth it? Intensive Care Med 2005;31:1145-7.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]
11.Liano F, Junco E, Pascual J, Madero R, Verde E. The spectrum of acute renal failure in the intensive care unit compared with that seen in other settings. The Madrid Acute Renal Failure Study Group. Kidney Int Suppl 1998;66:S16-24.  Back to cited text no. 11    
12.Mehta RL, Pascual MT, Soroko S, Chertow GM; PICARD Study Group. Diuretics, mortality and nonrecovery of renal function in acute renal failure. JAMA 2002;288:2547-53.  Back to cited text no. 12  [PUBMED]  [FULLTEXT]
13.Bellomo R, Ronco C, Kellum JA, Mehta RL, Palevsky P; Acute Dialysis Quality Initiative workgroup. Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: The Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group. Crit Care 2004;8:R204-12.  Back to cited text no. 13  [PUBMED]  [FULLTEXT]
14.Mehta RL, Kellum JA, Shah SV, Molitoris BA, Ronco C, Warnock DG, et al . Acute Kidney Injury Network (AKIN): Report of an initiative to improve outcomes in acute kidney injury. Crit Care 2007;11:R31.  Back to cited text no. 14  [PUBMED]  [FULLTEXT]
15.Bellomo R, Kellum JA, Ronco C. Defining acute renal failure: Physiological principles. Intensive Care Med 2004;30:33-7.  Back to cited text no. 15  [PUBMED]  [FULLTEXT]
16.Han WK, Bonventre JV. Biologic markers for the early detection of acute kidney injury. Curr Opin Crit Care 2004;10:476-82.  Back to cited text no. 16  [PUBMED]  [FULLTEXT]
17.Gruberg L, Mintz GS, Mehran R, Gangas G, Lansky AJ, Kent KM, et al . The prognostic implications of further renal function deterioration within 48 hours of interventional coronary procedures in patients with pre-existent chronic renal insufficiency. J Am Coll Cardiol 2000;36:1542-8.  Back to cited text no. 17  [PUBMED]  [FULLTEXT]
18.Praught ML, Shlipak MG. Are small changes in serum creatinine an important risk factor? Curr Opin Nephrol Hypertens 2005;14:265-70.  Back to cited text no. 18  [PUBMED]  [FULLTEXT]
19.Perrone RD, Madias NE, Levey AS. Serum creatinine as an index of renal function: New insights into old concepts. Clin Chem 1992;38:1933-53.  Back to cited text no. 19  [PUBMED]  [FULLTEXT]


  [Table - 1], [Table - 2]


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Indian Journal of Nephrology
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