Objective: The 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).
Design: Single-center retrospective study.
Setting: Academic medical center.
Participants and interventions: After 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.
Results: The 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/m(2)) had a significantly greater risk of developing AKICPB than those in lower BMI classes. BMI>40 kg/m(2) 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/m(2) cohort relative to BMI<25 kg/m(2) 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.
Conclusion: BMI>40 kg/m(2) is associated with a significantly higher risk of developing of AKICPB.
Keywords: BMI; acute kidney injury; cardiopulmonary bypass; morbid obesity.
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