Longitudinal dose and type of immunosuppression in a national cohort of Australian liver, heart, and lung transplant recipients, 1984-2006

Abstract

Unconfounded comparative data on the type and dose of immunosuppressive agents among solid organ transplant recipients are sparse, as are data on longitudinal immunosuppressive therapy since transplantation. We addressed this issue in a population-based cohort of Australian liver (n = 1895), heart (n = 1220), and lung (n = 1059) transplant recipients, 1984-2006. Data on immunosuppressive therapy were retrospectively collected at discharge, three months, and one, five, 10, and 15 yr after first transplant. We computed unadjusted and adjusted estimates for the association between the type and dose of immunosuppressive therapy and organ type. After adjustment for confounders, use of induction antibody and maintenance corticosteroids was more common in heart and lung compared to liver recipients (p < 0.001), and antibody therapy for rejection more common in liver recipients (p < 0.001). Liver recipients were more likely to receive calcineurin inhibitor monotherapy, with or without corticosteroids, compared to heart and lung recipients (p < 0.001). Liver recipients consistently received lower doses of azathioprine than heart and lung recipients (p < 0.001). These differences in immunosuppression may partly explain variations in immunosuppression-related morbidity by transplanted organ, for example, malignancy risk. Longitudinal changes in the type and the dose of immunosuppressive therapy over time since transplantation also demonstrate the need for time-dependent data in observational research.