highlights the fact that current criteria as defined by the International Ascites Club need revision. Current proposals for a working definition of HRS have largely adopted current AKI criteria,5 but we

need to recognize the clinical reality that not all patients who might be classified as having type 1 HRS should necessarily be included in one grouping, and this is where current AKI criteria or the new proposals let us down. This is not just about putting patients into brackets or classifying them, it is about understanding the mechanisms of disease. Further, the current RIFLE criteria and indeed the proposals put forward by Wong et al.5 put patients with refractory ascites into a group with chronic kidney disease, and yet much of the renal dysfunction is entirely reversible. Belcher et al. recognized this dilemma when they state “We have avoided using the selleck antibody term ‘chronic kidney disease’ as this classically implies structural damage. Many patients with cirrhosis have a chronically depressed GFR due instead to persistent hypoperfusion and their renal function may thus be partially reconstituted with restitution of perfusion. The article by Belcher et al.7 highlights the need for all new definitions of HRS to recognize that patients with cirrhosis may develop acute

kidney injury for a variety of reasons, many of which involve bacterial infection, or rapid decompensation of liver function (e.g., alcoholic hepatitis without infection), shock, administration of a nephrotoxic drug, as well as those having “true” chronic selleckchem kidney disease, rather than renal hypoperfusion. We need to be able to identify patients early, both as new patients and importantly those patients who develop AKI following admission to the hospital, since this latter group have a higher mortality, and this should be preventable.6 What is the purpose of a definition of HRS? Why not just group everyone together as recently proposed?5 The purpose is to recognize the different clinical entities that arise so that we do not group all patients as being one and equal, but classify them so that we can

increase our understanding of the underlying pathophysiology and MCE develop targeted therapies. While it is clear from the two largest trials of terlipressin in HRS2, 3 that not all patients respond to therapy, we need to identify the different clinical entities that may respond to different therapies, in the same way that pharmacogenomics is beginning to identify subsets of patients who respond to certain drugs. The article by Parikh et al. highlights the problems and dilemmas we face.6 There are major problems with the current definition of HRS, but there are also problems if we simply adopt AKI criteria. We need robust criteria to classify patients so that our future therapies are individualized to the patient, so that they can be more effective.