The Impact of Body Mass Index on the Duration of Hospital Stay After Cardiac Surgery

BACKGROUND: The impact of body mass index (BMI) on clinical outcomes after cardiac surgery remains controversial. The objective of this study was to evaluate the association between BMI and the duration of hospital stay in patients after cardiac surgery. METHOD: A retrospective, cross-sectional study was conducted with 1120 patients admitted to Beirut Cardiac Institute for cardiac surgery between July 2020 and July 2022. Patients were divided based on the BMI groups as follows: normal weight, overweight, obesity class I, obesity class II, and obesity class III. The length of hospital stay after cardiac surgery was compared among BMI groups after cardiac surgery, and also among each type of surgery. RESULTS: Of the 1120 patients who underwent cardiac surgery, 270 (24.1%) patients had normal BMI, 459 (41.0%) patients were overweight, and 391 (34.9%) patients were obese. The average length of hospital stay was 8.97 ± 5.88 days, with no correlation between BMI and length of hospital stay (r = 0.058; P = 0.052). Obesity class III patients experienced the longest stay (11.37 ± 7.09 days) with a significant difference compared to the length of hospital stay of normal weight patients (P = 0.007). Patients who underwent coronary artery bypass graft (CABG) surgery experienced the shortest duration of stay (8.50 ± 4.81 days) compared to the isolated valve surgery (9.46 ± 8.12 days) and combined CABG and valve surgery (10.52 ± 4.56 days; P ≤ 0.001). Within the CABG group, obesity class III patients had experienced the longest length of hospital stay (13.05 ± 8.85 days) with a significant difference compared to the length of hospital stay in normal weight patients (7.93 ± 3.11 days; P = 0.004). CONCLUSION: Our results demonstrated no correlation between BMI and length of hospital stay after cardiac surgery. However, the obesity class III patients within the CABG group had the longest length of hospital stay. These findings highlight the importance of shifting the focus of healthcare planning to obesity class III, particularly in the context of specific surgical procedures.