Abstract 21416: Variation Across Centers and Predictors of Initial Immunosuppression Strategy After Heart Transplant

Abstract

Background: There are multiple accepted immunosuppressive medication (ISM) strategies after heart transplant (HT) and evidence of their relative efficacy is limited. As a result, ISM strategies may vary considerably depending on local protocols. We aimed to characterize center-level variation and predictors of ISM strategy. Methods: Using data from the UNOS registry, we included 38,826 patients undergoing HT at 124 US centers from 1994 to 2014; centers with less than 30 transplants during this span were excluded (n=53). ISM strategies included 1) use of anti-lymphocyte induction therapy, 2) omission of corticosteroids (“steroid-free”) in the initial maintenance regimen, and 3) initial inclusion of mTOR inhibitors. Associations between the utilization of each strategy and other center-level characteristics were determined using chi-squared and Pearson correlation tests. Results: The mean center-level proportions of patients receiving induction, steroid-free, and mTOR inhibitor regimens were 50.2% (standard deviation (SD) = 24.6%), 4.3% (SD = 5.6%), and 2.4% (SD = 3.2%) respectively (Figure 1). Many centers (16.1%) used induction in nearly all (> 80%) of their patients and a similar proportion (21.0%) used induction infrequently (in < 20% of patients). While use of mTOR and steroid-free regimens was rare, 10 centers used one or both of these regimens in more than 10% of patients. Centers in the northeast less often used induction and steroid-free regimens were more often used in higher-volume centers (p <= 0.05). Conclusions: There is substantial variation across centers in ISM strategy after HT, particularly in the use of induction. This degree of variation is unlikely to be explained by differences in patient mix, and more likely stems from differences in provider preference. Further studies are needed to assess the underlying drivers and clinical impact of this variation.