Costs of drugs used after renal transplantation

There are no detailed data on the relative contributions to overall health care costs of the various drugs that are commonly used in renal transplant patients. We performed a cost analysis in 122 patients, using the medical records and our hospital administration service as data sources, for all health care-related costs during the first year after renal transplantation. During the first 3 months all patients were on cyclosporine (CsA) and prednisone. Subsequently, they were randomly allocated to CsA monotherapy or to conversion from CsA to azathioprine. Cost of drugs comprised about 25% of total health care expenses. In CsA-treated patients, the following costs per patient per year were calculated: CsA, DFL 9929 (1 DFL is about US$0.60; 67.5% of total drug costs); antilymphocyte agents, DFL 2613 (17.8%); other immunosuppressive drugs, DFL 455 (3.1%); antimicrobial agents, DFL 687 (4.7%); antihypertensive drugs, DFL 467 (3.2%); remaining drugs, DFL 554 (3.8%). Conversion from CsA to azathioprine resulted in a decrease in mean drug costs for the remainder of the first posttransplant year of DFL 4597 (P < 0.01). Although the incidence of acute rejections tended to be higher after steroid withdrawal than after conversion (39% versus 26%, not significant), the costs of anti-rejection therapy, hospitalization, and laboratory services did not differ. We conclude that CsA is the main determinant of overall drug costs. When compared to CsA monotherapy, conversion from CsA to azathioprine at 3 months after transplantation may result in subsequent cost savings of about DFL 5000 per patient per year without a higher incidence of rejection or graft loss.