Cost effectiveness of prophylactic intravenous immune globulin in chronic lymphocytic leukemia

A recent randomized controlled trial of intravenous immune globulin in patients with chronic lymphocytic leukemia and hypogammaglobulinemia demonstrated a statistically significant reduction in the rate of bacterial infections among patients who received intravenous immune globulin. We used decision-analysis techniques to determine whether prophylactic intravenous immune globulin is likely to result in an overall clinical benefit to patients who receive this treatment and to examine its cost effectiveness.

We constructed a model to compare two strategies: treatment with intravenous immune globulin at a dose of 400 mg per kilogram of body weight every three weeks and no immune globulin therapy. Baseline estimates of the efficacy of intravenous immune globulin were derived from the published results of the randomized trial. The costs of treatment, complications, and infections were estimated on the basis of component costs. Health outcomes were measured in terms of gains in quality-adjusted life expectancy.

Intravenous immune globulin therapy can result in a loss of quality-adjusted life expectancy when the inconvenience of treatment is taken into account. If the inconvenience of treatment is not considered, therapy results in a gain of 0.8 quality-adjusted days per patient per year of therapy at a cost of $6 million per quality-adjusted life-year gained.

Decision-analysis modeling may be applied to the results of randomized controlled trials to assess the potential clinical and financial effects of adopting the intervention in medical practice. In the case of intravenous immune globulin therapy in patients with chronic lymphocytic leukemia and hypogammaglobulinemia, this type of analysis suggests that treatment might not result in improved quality or length of life and that it is extraordinarily expensive in comparison with other treatments generally accepted as cost effective.