Acute kidney injury (AKI) occurs in approximately one-third of patients undergoing cardiac surgery (CS), and represents one of the most significant negative predictors of patient outcome in this population. The investigators sought to examine the risk factors associated with the development of AKI and renal recovery in patients undergoing cardiac surgery at San Bortolo Hospital, Italy 2014-2015.

Acute kidney injury (AKI) occurs in approximately one-third of patients undergoing cardiac surgery (CS), and represents one of the most significant negative predictors of patient outcome in this population. The investigators sought to examine the risk factors associated with the development of AKI and renal recoveryin patients undergoing cardiac surgery at San Bortolo Hospital, Italy during November 2014 - October 2015.

Inclusion Criteria:

- Adult cardiac surgery

Exclusion Criteria:

1. Missing baseline serum creatinine (defined as a serum creatinine value within 90 prior to surgery) or missing serum creatinine within 3 days before hospital discharge
2. Stage 5 chronic kidney disease (estimated glomerular filtration rate <15 ml/min/1.73 m2 or receipt of chronic dialysis)
3. Solid organ transplant recipients

Adult patients undergoing cardiac surgery (elective, urgent and emergent; coronary artery bypass, valve replacements, combined or other surgery, with cardiopulmonary bypass) between November 2014 and October 2015 at the Division of Cardiac Surgery, San Bortolo Hospital, in Vicenza, Italy