Variation in immunosuppression (ISx) for liver transplant (LTx) across US programs has not been described. We examined a novel database integrating national registry and pharmacy fill records for 24,238 LTx recipients (2008-2015). Bi-level hierarchical models were constructed to quantify impacts of program and clinical case factors on ISx choice; use of each regimen was compared pairwise to triple ISx (tacrolimus, antimetabolite, steroids). Metrics of heterogeneity included intraclass correlation (ICC), the ratio of program impact to total observed variance. Median odds ratios (MOR) provided median of the odds that patients with identical traits will receive a given regimen when 2 programs are randomly drawn.

In mo. 0-6, triple ISx was most common (42.9%). In mo. 7-12, ISx was most commonly antimetabolite-sparing (35.2%) and steroid-sparing (25.6%), followed by triple ISx (13.5%), mTOR inhibitor (mTORi) (11.9%), and cyclosporine (CsA) based (9.3%). However, use of all regimens varied widely across programs, from none to near-universal patterns (Fig).[figure1]After adjustment for case factors, ICCs suggest that substantial portions of variation in steroid-sparing (23%), antimetabolite-sparing (26%), mTORi (28%), and CsA-based (21%) use reflect “program effect.” MORs for each regimen in case-factor adjusted models ranged from 2.41 to 2.94.

While case factors explained <10% of variation, triple ISx in mo. 7-12 was more common among retransplant recipients and those with prior acute rejection (AR). Hepatocellular carcinoma as cause of liver failure (adjusted odds ratio, aOR 2.2, P<0.001), cancer within 6 mo. (aOR 6.38, P<0.001), and 6-mo eGFR <30 (aOR 2.0, P<0.001) were strongly associated mTORi use compared to triple ISx in months 7-12, while AR predicted lower use (aOR 0.72, P=0.003).

LTx ISx is dominantly driven by program preference, but case factors also affect regimen choice.

CITATION INFORMATION: Nazzal M, Ouseph R, Schnitzler M, Zhang Z, Axelrod D, Segev D, Naik A, Randall H, Brennan D, Kasiske B, Hess G, Alhamad T, Lentine K. National Variation in Liver Transplant Immunosuppression in the U.S.. Am J Transplant. 2017;17 (suppl 3).

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