Hospitalizations for opportunistic infections following transplantation and associated risk factors: A national cohort study of Medicare beneficiaries.

BACKGROUND:Opportunistic infections (OIs) are a significant cause of morbidity and mortality after organ transplantation, though data in the liver transplant (LT) population are limited. METHODS:We performed a retrospective cohort study of LT recipients between January 1, 2007 and Deceber 31, 2016 using Medicare claims data linked to the Organ Procurement and Transplantation Network database. Multivariable Cox regression models evaluated factors independently associated with hospitalizations for early (≤1 year post transplant) and late (>1 year) OIs, with a particular focus on immunosuppression. RESULTS:There were 11 320 LT recipients included in the study, of which 13.2% had at least one OI hospitalization during follow-up. Of the 2638 OI hospitalizations, 61.9% were early post-LT. Cytomegalovirus was the most common OI (45.4% overall), although relative frequency decreased after the first year (25.3%). Neither induction or maintenance immunosuppression were associated with early OI hospitalization (all p > .05). The highest risk of early OI was seen with primary sclerosing cholangitis (aHR 1.74; p = .003 overall). Steroid-based and mechanistic target of rapamycin inhibitor-based immunosuppression at 1 year post LT were independently associated with increased late OI (p < .001 overall). CONCLUSION:This study found OI hospitalizations to be relatively common among LT recipients and frequently occur later than previously reported. Immunosuppression regimen may be an important modifiable risk factor for late OIs.