Abstract Rationale Body mass index (BMI) may influence perioperative risk and recovery after lung transplantation, but evidence across clinically relevant BMI categories is mixed. We evaluated whether recipient BMI is associated with adverse postoperative outcomes post-transplant. Methods We performed a single-center retrospective cohort study of consecutive adult primary lung-only transplant recipients (April 2007-August 2025). Patients were stratified by BMI at transplant into three groups: A, 30, B, 30-34.9, and C, ≥35 kg/m². Cases with missing BMI were excluded. Data were abstracted from the institutional transplant registry and electronic health records. Continuous variables were summarized as median (IQR) and compared using the Kruskal-Wallis test; categorical variables as n (%) and compared by χ². Survival was estimated by Kaplan-Meier (KM) with Greenwood 95% CIs and compared using the two-sided log-rank test (α = 0.05). Twelve-month survival was derived from the KM curves. Results We analyzed 1,344 adult recipients stratified by BMI: 1,043 were in group A, 277 in group B, and 24 in group C. Wait-list time differed across groups (median IQR, A: 13 5-31 days; B: 11 5-25 days; and C: 19 9-31.8 days (p = 0.03). Recipients with higher BMI were younger at transplant (p = 0.007), with higher BMI groups being progressively younger (median age IQR, A: 65.0 57.5-69.0 years; B: 63.0 57.0-67.0 years, C: 59.0 56.5-61.2 years). Need for prolonged ventilator support ≥5 days post-transplant increased with BMI (A: 18.4%, B: 27.1%, C: 20.8%) as did rates of severe PGD at 72 hours (A: 22.6%, B: 33.9%, C: 33.3%, p = 0.01). Reintubation rates, postoperative ECMO use, and hospital length of stay did not differ significantly between groups. At 12 months, KM survival was 92.1% for A, 89.3% for B, and 91.5% for C. In age-adjusted Cox models, B showed higher mortality versus A (aHR 1.28, 95% CI 1.07-1.54; p = 0.01), while C did not differ (aHR 0.89, 95% CI 0.48-1.66; p = 0.72). Age was not independently associated with mortality (aHR per year 1.00, 95% CI 1.00-1.01; p = 0.32). Conclusions Lung transplantation in obese patients with BMI 30 tends to be associated with increased risk of primary graft dysfunction and prolonged ventilation needs after transplant. At our center, obese patients undergoing lung transplant were younger than the non-obese. With this age confounder, overall survival seemed to be comparable across BMI groups. This abstract is funded by: None
Muldiiarov et al. (Fri,) studied this question.