Temporal and spatial variability of immunosuppressive therapies in transplant patients: An observational study in Italy.

Background:In immunosuppression after transplantation, several multi-drug approaches are used, involving calcineurin inhibitors (CNI: tacrolimus-TAC or cyclosporine-CsA), antimetabolites (antiMs), mammalian target of rapamycin inhibitors (mTORis), and corticosteroids. However, data on immunosuppressive therapy by organ and its space-time variability are lacking. Methods:An Italian multicentre observational cohort study was conducted using health information systems. Patients with incident transplant during 2009-2019 and resident in four regions (Veneto, Lombardy, Lazio, and Sardinia) were enrolled. The post-transplant immunosuppressive regimen was evaluated by organ, region, and year. Results:The most dispensed regimen was triple-drug therapy for the kidneys [tacrolimus (TAC) + antiM + corticosteroids = 41.5%] and heart [cyclosporin  + antiM + corticosteroids = 36.6%] and double-drug therapy for liver recipients (TAC + corticosteroids = 35.4%). Several differences between regions and years emerged with regard to agents and the number of drugs used. Conclusion:A high heterogeneity in immunosuppressive therapy post-transplant was found. Further studies are needed in order to investigate the reasons for this variability and to evaluate the risk-benefit profile of treatment schemes adopted in clinical practice.