Bodyweight affects mortality in an L-shape pattern in patients undergoing coronary bypass grafting.

Background: The role of body composition as a risk factor for adverse outcomesduring coronary artery bypass surgery (CABG) has been controversial. The goal of this study was to evaluate the effect of body weight on mortality in patients undergoing CABG.

Method: Using a large NIS database and ICD-10 coding for different bodyweight categories, we evaluated the effect of cachexia, overweight, obesity, and morbid obesity on in-hospital mortality after CABG.  We evaluated the available database containing ICD10 coding from 2016- 2020.

Results: We found that cachexia was the strongest independent predictor of in-hospital mortality whereas obesity had a protective effect. Over the 4-year sample size, patients with cachexia had nearly a 4-fold increase in mortality compared to patients with normal weight despite adjusting for age and comorbidities (4.06 CI 2.7-6.0, p < 0.001). Patients with overweight and Obesity had the lowest mortality (OR = 0.44 CI 0.29-0.66, OR = 0.58 CI 0.52-0.63, p, 001). However, the mortality benefit disappeared in patients with morbid obesity (OR 0.9, CI 0.84-1.03, p = 0.15) with a trend of higher mortality in patients with morbid obesity after multivariate adjustment.

Conclusion: Cachexia is a powerful predictor for in-hospital mortality in patients undergoing CABG. Overweight and obesity have protective effect which disappears with morbid obesity.