Center-driven and clinically driven variation in US liver transplant maintenance immunosuppression therapy: A national practice patterns analysis

Abstract

Background. Variation in the use of immunosuppression regimens after liver transplant has not been well described. Methods. Immunosuppression regimens used after liver transplant were identified in a novel database integrating national transplant registry and pharmacy fill records for 24 238 recipients (2006-2014). Bilevel hierarchical models were developed to quantify the effects of transplant program, recipient, and donor characteristics on regimen choice. Results. In the first 6 months after transplant, triple immunosuppression (tacrolimus, antimetabolite, corticosteroids) was the most common regimen (42.9%). By months 7 to 12, immunosuppression regimens were more commonly antimetabolite sparing (33.7%) or steroid sparing (26.9%), followed by triple (14.4%), mammalian target of rapamycin inhibitor (mTORi)-based (12.1%), or cyclosporine-based (9.2%). Based on intraclass correlation analysis, clinical characteristics explained less than 10% of the variation in immunosuppression choice, whereas program preference/practice explained 23% of steroid sparing, 26% of antimetabolite sparing, 28% of mTORi, and 21% of cyclosporine-based regimen use. Although case factors were not dominant practice drivers, triple immunosuppression in months 7 to 12 was more common among retransplant recipients and those with prior acute rejection. Hepatocellular carcinoma as cause of liver failure (adjusted odds ratio [aOR], 2.15; P<0.001), cancer within 6 months (aOR, 6.07; P<0.001), and 6-month estimated glomerular filtration rate less than 30 mL/min per 1.3 m 2 (aOR, 1.98; P<0.001) were associated with mTORi use compared with triple immunosuppression in months 7 to 12, whereas acute rejection predicted lower use (aOR, 0.72; P=0.003). Conclusions. Liver transplant immunosuppression is dominantly driven by program preference, but case factors also affect regimen choice. This variation frames a natural experiment for future evaluations of comparative efficacy.