Fluconazole versus oral polyenes in the prophylaxis of immunocompromised patients: a cost-minimization analysis

This study compares 100 mg daily fluconazole with oral polyenes four times daily in the prophylaxis of fungal infections in immunocompromised patients, to determine a cost-minimization strategy. Data was gathered through a literature survey and clinical interviews conducted in nine different UK hospitals. This was used to construct a decision tree, modelling the drug choices available to a clinician at various stages of a patient's treatment, and assigning probabilities to the different corresponding outcomes. UK cost data were fed into this model to determine the expected cost per patient of the different prophylaxis strategies. Two different patient groups were considered: chemotherapy-only patients, and bone-marrow-transplant (BMT) patients who have higher risks of fungal infection. Probabilities derived from the literature suggest that a cost-minimization strategy to manage both chemotherapy patients and BMT patients is to administer oral fluconazole, both as prophylaxis and as first line treatment, against superficial fungal infection. Probabilities gathered from clinical interviews yield similar results, suggesting that the cost-minimization strategy with chemotherapy-only patients is to administer oral polyenes as prophylaxis, and oral fluconazole in case of superficial fungal infection, while for BMT patients it is a combination of fluconazole and oral polyenes as prophylaxis, with oral fluconazole for the treatment of superficial fungal infections. Using the probabilities from the literature, the lowest cost strategies produce an expected cost of pounds 567.20 for chemotherapy-only patients, and an expected cost of pounds 804.87 for BMT patients for a course of treatment lasting from seven to 28 days. The clinical interview probabilities produce expected costs of pounds 826.48 and pounds 1529.43, respectively. Sensitivity analysis was then conducted, and it was found that in the majority of cases, using the literature probabilities, the cost-minimizing strategy remained prophylaxis with oral fluconazole. The sensitivity analysis for chemotherapy-only patients using the interview probabilities tended to favour oral polyenes as the cost-minimization strategy, whereas for BMT patients the sensitivity analysis favoured a combination of fluconazole and oral polyenes in the majority of cases. The key economic advantage of prophylaxis with fluconazole or a combination of fluconazole with oral polyenes in the prophylaxis of fungal infection in immunocompromised patients, results from the reduction of the expected cost of subsequent fungal infection among those who are most at risk.