Figure 4.

Continuous associations between pretransplant plasma leptin level and the predicted risk of death at 1 year after transplantation in the Lung Transplant Outcomes Group Cohort. Green = lung transplant recipients not exposed to cardiopulmonary bypass (CPB) during transplant surgery. Blue = lung transplant recipients exposed to CPB during transplant surgery. Thick dotted lines = smoothed regression lines in 599 adult lung transplant recipients adjusted for body mass index category, age, recipient sex, lung allocation score, diagnosis (chronic obstructive pulmonary disease includes α₁-antitrypsin disease), donor sex, donor smoking history, ischemic time, transplant type (single vs. bilateral), mechanical ventilation, transplant year, and transplant center. Thin dashed lines = 95% confidence bands. Leptin levels were natural log transformed. CPB-stratified models are presented (P for interaction = 0.03). The P values for linearity are 0.15 for CPB users and 0.33 for nonusers, suggesting a lack of evidence that the associations are nonlinear. The P values for the association between leptin and mortality are 0.39 for CPB users and 0.03 for nonusers. These results suggest higher leptin levels are associated with an increased risk of death after lung transplantation among those who did not undergo CPB during transplant surgery.