Mixed-Effects Model for 1-year Treated-Acute Rejection Rate
In model A, which assessed the effect of each center as a random parameter, the standard deviation for the center effect for drug-treated rejection within 1-year post OHT was 0.66 [95% confidence interval (CI) 0.56, 0.78, p<0.001] (Table 2). This variability is further evidenced by the finding that 42 of the CIs from the 100 centers did not overlap the average center effect line (Supplementary Figure 1). After adjusting for year of transplantation and recipient and donor risk factors as fixed parameters (model B), the standard deviation for the center effect increased to 0.68 (95% CI 0.57, 0.79, p<0.001). The variables transplant year, recipient age, recipient gender, and HLA mismatch were significantly associated with 1-year treated rejection. In Model C, after introducing induction therapy at the patient-level as a fixed parameter, no significant association was identified between induction therapy use and 1-year rejection rate (OR 0.93, 95% CI 0.83-1.03; p=0.20). The VPC for model B and C was 12.5%, further suggesting there is substantial center variation in rejection rates attributable to other unmeasured centers characteristics without any impact by the inclusion of induction therapy parameter.