Obesity and Post-Cardiopulmonary Bypass-Associated Acute Kidney Injury: A Single-Center Retrospective Analysis

ObjectiveThe authors specifically explored the association of obesity (based on body mass index [BMI]) and the risk of developing acute kidney injury after cardiopulmonary bypass (AKICPB).DesignSingle-center retrospective study.SettingAcademic medical center.Participants and InterventionsAfter IRB approval, 376 eligible adults who underwent cardiac surgery with cardiopulmonary bypass between 2006-2010 were included in the final retrospective analysis. Patients undergoing “off-pump” procedures, cardiac transplants, repair of congenital heart disease, and patients with preoperative circulatory assist devices were excluded.ResultsThe overall incidence of developing AKICPB in this population based on the Acute Kidney Injury Network serum creatinine criteria was 39% (147 of 376). Among the BMI classes, the morbidly obese cohort (ie, BMI>40 kg/m2) had a significantly greater risk of developing AKICPB than those in lower BMI classes. BMI>40 kg/m2 was significantly associated with development of AKICPB even after accounting for covariates (ie, diabetes mellitus, hypertension, age, severity of illness, and CPB time) (overall p = 0.018). The odds ratio of AKICPB in the BMI>40 kg/m2 cohort relative to BMI<25 kg/m2 was 2.39 (95% CI: 0.98, 5.82; p = 0.055), with no significant difference in risk of developing AKICPB among the 4 lower BMI classes.ConclusionBMI>40 kg/m2 is associated with a significantly higher risk of developing of AKICPB.