Cost-effectiveness of three transdermal nitroglycerin controlled-release systems

We performed cost-effectiveness analyses of three transdermal nitroglycerin systems--TDN, ND II, and NTS--using data from two studies that compared these systems in terms of adhesive properties, patients' preferences, and skin tolerability. The purpose of our analysis was to determine which system achieved treatment objectives at the lowest cost. On the basis of data from the first of the two studies, the better adhesion and tolerability profile of TDN in comparison with ND II resulted in a savings of 2.8% and 4.4% at the wholesale and retail levels, respectively, for TDN over a four-week period. In a multivariate regression analysis of these data, the savings with TDN increased to 11% at wholesale prices and 12.7% at retail prices. For Study 2, retail and wholesale costs were found to be lower with the NTS patch than with the TDN patch in both the direct comparison and the multivariate analysis. However, extremely high rates of adverse reactions at the site of patch application-42%-and withdrawals due to adverse effects-64%-were noted in the NTS group; the corresponding rates in the TDN group were 2% and 0%. As a result, the cost advantage noted for the NTS patch was eliminated when the superior adhesion and tolerability characteristics of the TDN patch were considered in the analysis of the overall costs to the patient.