The Economic Consequences of Cardiac Surgery Associated Acute Renal Dysfunction After Heart Surgery

The Society of Thoracic Surgeons definition of acute renal failure requires a 3-fold rise in creatinine, creatinine > 4 mg/dL (with at least 0.5mg/dL rise from preoperative value), or new hemodialysis requirement. This definition does not capture the incidence, clinical impact, and economic burden of lesser degrees of acute renal dysfunction. A retrospective cohort study using discharge data from 650 hospitals was extracted from the Premier administrative database (2010-2014) for index cardiac cases (isolated coronary artery bypass grafting, isolated valve, and coronary artery bypass grafting-valve). We documented acute renal dysfunction through International Classification of Diseases (ICD) 9-CM codes and hospital charges, excluding those patients with pre-existing renal dysfunction. The incidence, length of stay , and total hospital costs associated with renal dysfunction for each of the index procedures were captured. The results reported are unadjusted for demographic and clinical factors. A total of 200,471 procedures were available for analysis in the database. The mean age was 66 years, 68.2% were male and 74% were white. Based on ICD 9-CM codes and hospital charges for these cases, 27,216 (13.6%) patients had some level of renal dysfunction. In addition to increase in length of stay, patients who developed renal dysfunction had an associated 57-85% increase in total cost of hospitalization. The incidence of renal dysfunction in this study is higher than reported previously. The Society of Thoracic Surgeons definition of renal failure captures only severe disease and may miss lesser degrees of dysfunction, which nonetheless have an impact on patient outcome and costs.