Substantial preoperative weight loss increases odds of healthcare utilization after reduction mammoplasty in obese patients

Background Obesity is associated with increased complications following reduction mammoplasty (RM). Preoperative weight loss is commonly recommended to reduce surgical risk, although it remains unclear whether obese patients who have recently lost weight experience outcomes comparable to their weight-stable obese counterparts. This study evaluated the impact of recent preoperative weight loss on postoperative outcomes following RM. Methods Epic COSMOS was used to identify obese patients undergoing RM. Patients who lost ≥5% body weight within two years before surgery were compared with weight-stable controls. Postoperative complications were assessed. Propensity score matching and multivariable regression were used to adjust for covariates. Results After matching, 7,874 patients were included in each cohort. Patients with substantial (>10% body weight) weight loss demonstrated highest risk of surgical site infection [SSI] (aOR 1.26; 95% CI 1.04 – 1.52) and more than double the risk of hospital readmission (aOR 2.09, 95% CI 1.31 – 3.25). Independent of weight loss, severe morbid obesity (BMI 40–50) was associated with increased risk of SSI (aOR 1.77, 95% CI 1.48 – 2.1), wound dehiscence (aOR 2.24, 95% CI 1.81 – 2.77), fat necrosis (aOR 1.51; 95% CI 1.11-2.01), and ED revisit (aOR 1.49, 95% CI 1.21 – 1.82). Conclusion In obese patients, preoperative weight loss exceeding 10% of body weight was associated with higher odds of SSI and hospital readmission following RM compared with weight-stable obese counterparts. Given the observational design and unmeasured factors including nutritional status and frailty, no broader inference regarding the effect of preoperative weight loss on surgical risk is drawn.