Reply to: "To close the stable door before the horse has bolted".

Evaluation of the Acute Kidney Injury Network criteria in hospitalized patients with cirrhosis and ascitesJournal of HepatologyVol. 59Issue 3PreviewFor several years hepatologists have defined acute renal failure in patients with cirrhosis as an increase in serum creatinine (sCr) ⩾50% to a final value of sCr >1.5 mg/dl (conventional criterion). Recently, the Acute Kidney Injury Network (AKIN) defined acute renal failure as acute kidney injury (AKI) on the basis of an absolute increase in sCr of 0.3 mg/dl or a percentage increase in sCr ⩾50% providing also a staging from 1 to 3. AKIN stage 1 was defined as an increase in sCr ⩾0.3 mg/dl or increase in sCr ⩾1.5-fold to 2-fold from baseline. Full-Text PDF To close the stable door before the horse has boltedJournal of HepatologyVol. 60Issue 3PreviewWe read with interest the studies by Fagundes and colleagues [1], Piano and colleagues [2] and the accompanying editorial [3]. Full-Text PDF Open AccessA modified acute kidney injury classification for diagnosis and risk stratification of impairment of kidney function in cirrhosisJournal of HepatologyVol. 59Issue 3PreviewThe Acute Kidney Injury Network (AKIN) criteria are widely used in nephrology, but information on cirrhosis is limited. We aimed at evaluating the AKIN criteria and their relationship with the cause of kidney impairment and survival. Full-Text PDF We read with great interest the letter by Thalheimer and Burroughs in relation to our study and that of Piano et al. [1Fagundes C. Barreto R. Guevara M. Garcia E. Sola E. Rodriguez E. et al.A modified acute kidney injury classification for diagnosis and risk stratification of – impairment of kidney function in cirrhosis.J Hepatol. 2013; 59: 474-481Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar, 2Piano S. Rosi S. Maresio G. Fasolato S. Cavallin M. Romano A. et al.Evaluation of the acute kidney injury network criteria in hospitalized patients with cirrhosis and ascites.J Hepatol. 2013; 59: 482-489Abstract Full Text Full Text PDF PubMed Scopus (187) Google Scholar] recently published in Journal of Hepatology. We appreciate their interesting and stimulating comments as they contribute to scientific interaction on a very important topic. We absolutely agree with their comment that the results of our study should be interpreted in the perspective that patients were hospitalized in a Liver Unit and complications of cirrhosis were managed according to international guidelines [[3]EASL Ginès P. Angeli P. Lenz K. Moller S. Moore K. et al.EASL Clinical Practice Guidelines on the management of ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome in cirrhosis.J Hepatol. 2010; 53: 397-417Abstract Full Text Full Text PDF PubMed Scopus (1322) Google Scholar]. Having said that, one of the main messages of our study is that in cirrhosis AKI stage 1 group is constituted by a heterogeneous population with respect to prognosis, and that two very different subsets of patients can be easily identified according to peak serum creatinine reached during the AKI episode. A first subgroup, AKI stage 1a with a peak serum creatinine ⩽1.5 mg/dl, that has a 3-month survival close to that of patients without AKI, and a second subgroup, AKI stage 1b, with a peak serum creatinine >1.5 mg/dl. Patients from this latter group have a much worse prognosis, which is intermediate between those of patients without AKI and patients with stage 2 AKI. In our study, it is not stated that AKI stage 1a is a benign condition. A simple look at Fig. 3 (graph A) of the study by Fagundes et al. [[1]Fagundes C. Barreto R. Guevara M. Garcia E. Sola E. Rodriguez E. et al.A modified acute kidney injury classification for diagnosis and risk stratification of – impairment of kidney function in cirrhosis.J Hepatol. 2013; 59: 474-481Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar] shows that 3-month probability of survival in the group of patients with AKI stage 1a is of 84%, which is not really a prognosis of a “benign” condition. The incorporation of a maximum level of serum creatinine reached (such as the 1.5 mg/dl used in our study) to the AKI criteria makes pathophysiological sense because it adds a threshold to define kidney dysfunction. As an example, let’s imagine two patients with baseline serum creatinine of 0.5 mg/dl and 1.3 mg/dl respectively, who develop AKI stage 1 based on an increase of 0.3 mg/dl in both cases. While in the former a peak of serum creatinine of 0.8 mg/dl indicates that glomerular filtration rate is still normal, in the latter a peak of 1.6 mg/dl indicates impaired organ function (markedly reduced glomerular filtration). At these levels of glomerular filtration rate, the minimum GFR reached (which corresponds to the peak serum creatinine) has more prognostic information than a relative increase of 0.3 mg/dl. This statement is not opinion-based, it is based on data from two different prospective studies that included a large number of patients. In summary, the studies by Piano et al. and Fagundes et al. [1Fagundes C. Barreto R. Guevara M. Garcia E. Sola E. Rodriguez E. et al.A modified acute kidney injury classification for diagnosis and risk stratification of – impairment of kidney function in cirrhosis.J Hepatol. 2013; 59: 474-481Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar, 2Piano S. Rosi S. Maresio G. Fasolato S. Cavallin M. Romano A. et al.Evaluation of the acute kidney injury network criteria in hospitalized patients with cirrhosis and ascites.J Hepatol. 2013; 59: 482-489Abstract Full Text Full Text PDF PubMed Scopus (187) Google Scholar] convincingly demonstrate, in 2 independent series of patients, that the incorporation of a peak serum creatinine of 1.5 mg/dl in stage 1 of the AKIN criteria provides very useful clinical information in cirrhosis as it allows stratifying these patients into two different subgroups with markedly different prognosis. The authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.