Risk prediction of 90-day complications in implant-based breast reconstruction -does previous post-bariatric massive weight loss add to the risk? A population-based study.

INTRODUCTION

Risk stratification is essential when selecting the timing and technique of breast reconstruction. While several prediction models exist, none have incorporated prior massive weight loss (MWL), despite a growing population of such patients. This study aimed to develop cumulative risk prediction models for complications after implant-based breast reconstruction, explicitly including MWL as a candidate predictor.

METHODS

This nationwide, population-based case-control study used prospectively collected Swedish registry data. Patients with prior bariatric surgery who underwent immediate or delayed post-mastectomy implant-based breast reconstruction between 2007 and 2022 were identified and matched to at least 3 controls by age and body mass index. Candidate predictors were selected based on prior literature. Group least absolute shrinkage and selection operator (LASSO) regression with bootstrap resampling was used to develop prediction models, which were visualized as nomograms.

RESULTS

A total of 245 immediate and 602 delayed breast reconstructions were included; 11% and 6%, respectively, had a history of MWL. Complication rates were 16.3% for immediate and 14.5% for delayed reconstruction. Prior MWL was consistently selected as an independent predictor of complications in both immediate and delayed reconstruction models and of re-admission after delayed reconstruction. Other predictors included age, body mass index, radiotherapy, comorbidity-related medications, and antibiotic use.

CONCLUSION

Prior massive weight loss following bariatric surgery is an independent risk factor for complications after both immediate and delayed implant-based breast reconstruction. Incorporating MWL into cumulative risk prediction models improves individualized risk assessment and supports informed, shared decision-making in reconstructive breast surgery.