The Impact of Body Mass Index on Surgical Outcomes in Gender-Affirming Mastectomy

Purpose: This study is a retrospective analysis of the impact of body mass index (BMI) on postoperative complications in patients undergoing gender-affirming mastectomy. Methods: Patients were classified as normal, overweight, Class I obese, Class II obese, and Class III obese. In addition, obese patients were organized as metabolically healthy obese or metabolically unhealthy obese. Patients were monitored for postoperative complications for 30 days postoperatively. Results: There were 644 eligible patients (187 normal, 175 overweight, 130 Class I obese, 75 Class II obese, and 77 Class III obese). Univariate analysis revealed a difference in rates of total hematoma ( p = 0.041), minor contour abnormalities ( p < 0.001), and revision surgery ( p = 0.011). Upon multivariate analysis, BMI was not associated with an increased risk of any complications. Diabetes was associated with increased rates of total hematoma (odds ratio [OR]: 6.332434, 95% confidence interval [CI]: 1.755549–22.84170, p = 0.005), and hematoma requiring evacuation (OR: 5.356774, 95% CI: 1.197319–23.966070, p = 0.028). Age was associated with increased rates of minor contour abnormalities (OR: 1.043112, 95% CI: 1.001189–1.086791, p = 0.044) and revision surgery (OR: 1.062360, 95% CI: 1.010353–1.117046, p = 0.018). Of the 282 obese patients, 240 patients were metabolically healthy obese, while 42 were metabolically unhealthy obese. Metabolically unhealthy obesity was associated with an increased risk of hematoma formation in both univariate ( p = 0.005) and multivariate analyses (OR: 3.603872, 95% CI: 1.009268–12.868620, p = 0.048). Conclusion: BMI alone should not exclude patients from receiving gender-affirming mastectomy.