AUTHOR=Elbaz-Greener Gabby , Rozen Guy , Carasso Shemy , Kusniec Fabio , Yarkoni Merav , Marai Ibrahim , Strauss Bradley , Wijeysundera Harindra C. , Smart Frank W. , Erez Eldad , Alcalai Ronny , Planer David , Amir Offer 

TITLE=The Relationship Between Body Mass Index and In-Hospital Mortality in Patients Following Coronary Artery Bypass Grafting Surgery

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.754934

DOI=10.3389/fcvm.2021.754934

ISSN=2297-055X

ABSTRACT=Background: The association between Body Mass Index (BMI) and clinical outcomes following coronary artery bypass grafting (CABG) remains controversial.  Our objective was to investigate the real-world relationship between BMI and in-hospital clinical course and mortality, in patients who underwent CABG
Methods: A sampled cohort of patients who underwent CABG between October 2015 and December 2016 was identified in the National Inpatient Sample (NIS) database.   Outcomes of interest included in-hospital mortality, peri-procedural complications and length of stay.  Patients were divided into 6 BMI (kg/m2) subgroups; (1) under-weight ≤19, (2) normal-weight 20-25, (3) over-weight 26-30, (4) obese I 31-35, (5) obese II 36-39, and (6) extremely obese ≥40.  Multivariable logistic regression model was used to identify predictors of in-hospital mortality.  Linear regression model was used to identify predictors of length of stay (LOS).
Results: An estimated total of 48,710 hospitalizations for CABG across the U.S. were analyzed.  The crude data showed a U-shaped relationship between BMI and study population outcomes with higher mortality and longer LOS in patients with BMI ≤19kg/m2 and in patients with BMI ≥40kg/m2 compared to patients with BMI 20-39kg/m2.  In the multivariable regression model, BMI subgroups of ≤19kg/m2 and ≥40kg/m2 were found to be independent predictors of mortality. 
Conclusions:  A complex, U-shaped relationship between BMI and mortality was documented, confirming the "obesity paradox" in the real-world setting, in patients hospitalized for CABG.