A retrospective study on the utilization of and expenditure for immunosuppressants for organ transplant recipients in Taiwan--updated to 2006.

We sought to examine the utilization of and expenditure for immunosuppressants among transplant recipients under the Taiwan global budget system updated from 2004 to 2006, as provided by the Taiwan Longitudinal Health Insurance Database (2005). By using all ambulatory care orders (OO) of files from 2002 to 2006, we identified immunosuppressive agents by the Anatomic Therapeutic Chemical (ATC) code. We selected and analyzed all immunosuppressants classified into the L04 group. For the analytic work, a generalized linear model was developed to examine the effect of time and different ATC subgroup immunosuppressants on drug expenditures. Compared with the previous report covering 1999-2003, wherein the most frequently prescribed immunosuppressive agents were cyclosporine (43%), mycophenolate (30.8%), and tacrolimus (21.3%), the updated information showed cyclosporine 36.8%, tacrolimus 30.17%, and mycophenolate 21.46%. In 2005, the total drug expenditure for tacrolimus was higher than for cyclosporine which was the major immunosuppressive agent used previously. Wald chi-square tests on the effect of time from 2001 to 2006 with different immunosuppressive drug classes showed a significant result (P<.01), namely, increased drug expenditures over time owing to different ATC classes of immunosuppressants. Projecting drug expenditure using a pharmacoepidemiology approach could show the overall picture of cost utilization, including the complex determinants of price inflation, utilization, and physician behavior.
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