The association between BMI and postoperative pulmonary complications in adults undergoing non‐cardiac, non‐obstetric surgery: a retrospective cohort study

INTRODUCTION: Conflicting results have been reported regarding the influence of BMI on postoperative adverse events. The aim of this study was to investigate the association between BMI and postoperative pulmonary complications in adults undergoing non-cardiac, non-obstetric surgical procedures. METHODS: This large-scale retrospective study included 125,082 adults who underwent surgery at a university-affiliated tertiary care hospital between 2019 and 2023. The primary endpoint was the incidence of postoperative pulmonary complications. Multivariable logistic regression analyses, subgroup analyses, sensitivity analyses and restricted cubic splines were used to assess the association between BMI and postoperative pulmonary complications. RESULTS: . DISCUSSION: Patients who were overweight or living with class 1 obesity undergoing non-cardiac, non-obstetric surgery had paradoxically lower risks of postoperative pulmonary complications compared with those of a normal weight. These findings may contradict traditional assumptions about surgical risk and obesity, highlighting the need to re-evaluate the relationship between BMI and postoperative pulmonary complications.