MGB6 Formulary Impact Decision Modeling in HMG-COA Reductase Inhibitors

Abstract

According to the NHANES III data, a majority of patients require 20–30% reduction in their LDL-cholesterol to achieve their NCEP goal. Fluvastatin, a HMG-CoA reductase inhibitor (statin), has been shown to be both safe and effective in achieving 20–30% reductions in LDL cholesterol, and of all the statins, it has the lowest drug acquistion cost. OBJECTIVE: The purpose of this model was to assess the economic impact of using a two-drug formulary that includes fluvastatin and another statin, versus a one-statin ormulary. METHODS: In a hypothetical cohort of 10,000 patients, a two-drug formulary with fluvastatin as the statin of choice for mild to moderate LDL-cholesterol reduction and another agent for those patients requiring additional reduction was compared with a one-drug formulary of atorvastatin, pravastatin, or simvastatin. NHANES III data was utilized to estimate the percentage of patients requiring <30% or ≥ 30% LDL-cholesterol reduction. Doses used in this model were the average daily doses required for adequate LDL reduction as estimated by 1997 IMS data, and costs of drug therapy using a weighted AWP. The cost savings was estimated by subtracting the combined drug acquisition costs of the two statins from the cost of a single statin prescribed for 100% of the patients. Sensitivity analyses were also performed on key parameters of the model. RESULTS: Based on NHANES III estimation, over 70% of patients would require a <30% LDL-cholesterol reduction. A two-drug formulary using fluvastatin was shown to provide more cost savings than a single-drug formulary using any of the other agents, with annual cost difference ranging from $1.2 million to $3 million per 10,000 patients. CONCLUSIONS: Using formulary modeling, managed care decision-makers can measure the economic impact of their statin choice. This model demonstrates the economic benefit of using fluvastatin in formulary management.