Mild Stage 1 post-operative acute kidney injury : association with chronic kidney disease and long-term survival

• Published in: Clinical Kidney Journal
• Main Authors: Long, Thorir Einarsson, Helgason, Dadi, Helgadottir, Solveig, Sigurdsson, Gisli Heimir, Palsson, Runolfur, Sigurdsson, Martin Ingi, Indridason, Olafur Skuli
• Format: Article in Journal/Newspaper
• Language: English
• Published: Uppsala universitet, Anestesiologi och intensivvård 2021
• Subjects: acute kidney injury; chronic kidney disease; KDIGO criteria; serum creatinine; survival; Urology and Nephrology; Urologi och njurmedicin; Iceland
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-443033; https://doi.org/10.1093/ckj/sfz197

Background. Mild cases of acute kidney injury (AKI) are identified by a small rise in serum creatinine (SCr) according to the KDIGO AKI definition. The aim of this study was to examine the long-term outcomes of individuals with mild AKI. Methods. This was a retrospective cohort study of all adult patients who underwent abdominal, cardiothoracic, vascular or orthopaedic surgery at Landspitali-The National University Hospital of Iceland in 1998-2015. Incident chronic kidney disease (CKD), progression of pre-existing CKD and long-term survival were compared between patients with mild Stage 1 AKI (defined as a rise in SCr of >= 26.5 mu mol/L within 48h post-operatively without reaching 1.5 x baseline SCr within 7 days), and a propensity score-matched control group without AKI stratified by the presence of CKD. Results. Pre- and post-operative SCr values were available for 47333 (42%) surgeries. Of those, 1161 (2.4%) had mild Stage 1 AKI and 2355 (5%) more severe forms of AKI. Mild Stage 1 AKI was associated with both incident CKD and progression of pre-existing CKD (P < 0.001). After exclusion of post-operative deaths within 30 days, mild Stage 1 AKI was not associated with worse 1-year survival in patients with preserved kidney function (94% versus 94%, P = 0.660), and same was true for patients with pre-operative CKD (83% versus 82%, P = 0.870) compared with their matched individuals. Conclusions. Mild Stage 1 AKI is associated with development and progression of CKD, but not with inferior 1-year survival. These findings support the inclusion of a small absolute increase in SCr in the definition of AKI.