Results
The costs of the two treatment alternatives in the model are shown in table III . The mean expected cost per episode of invasive aspergillosis treated in an average patient (mean bodyweight of 68.6kg) was obtained by adding the weighted cost of the adverse reactions plus the cost of treatment (acquisition and administration). Thus, according to the incidences of adverse reactions reported for the two drugs, the mean cost per patient with invasive aspergillosis treated with voriconazole was €6041.93 (IV treatment acquisition cost €5524.75), while with caspofungin this increased to €7174.05 (IV treatment acquisition cost €6672.80). This means that for each patient with aspergillosis treated with IV voriconazole in the hospital, a savings of €1132.18 would be achieved compared with use of caspofungin.
Sensitivity Analysis
Figure 1 shows the expected costs for each bodyweight and the threshold value at which the costs of treatment of the disease with both drugs were equal; differences favoured voriconazole at bodyweights <103.42kg. The results were robust when the duration of IV and oral treatment was varied simultaneously, as well as the bodyweight of the patient, as shown in figure 2.
Figure 1.
Univariate sensitivity analysis of the treatment of invasive aspergillosis with voriconazole or caspofungin. Cost-effectiveness results for both treatment arms were obtained for different bodyweights of patients while maintaining all other assumptions and inputs from the base-case scenario. Voriconazole was more cost effective than caspofungin at bodyweights <103.42kg.
Figure 2.
Bivariate sensitivity analysis of treatment of invasive aspergillosis with voriconazole and caspofungin. Cost-effectiveness results for both treatment arms were obtained using the upper and lower limits of the CI (95%) for intravenous (IV) and oral treatment duration and patient bodyweight. Voriconazole was more cost effective than caspofungin at bodyweights <104.21kg when the duration of IV and oral treatment was maximum (95% CI), and more cost effective than caspofungin at bodyweights <102.04kg when the duration of IV and oral treatment was minimum (95% CI).
These results indicate that the cost of treatment of invasive aspergillosis with voriconazole in sequential therapy (IV and oral) was lower than with IV caspofungin plus oral continuation therapy (voriconazole), even when the duration of IV and oral treatment were maximised and minimised within a plausible range (95% CI). These differences are favourable to voriconazole for bodyweights <104.21kg if duration of IV and oral treatment is maximum (95% CI), and <102.04kg if duration is minimum (95% CI).
Clin Drug Invest. 2007;27(3):197-205. © 2007 Adis Data Information BV
Cite this: Economic Evaluation of Voriconazole versus Caspofungin for the Treatment of Invasive Aspergillosis in Spain - Medscape - Mar 01, 2007.
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