Objective: The clinical literature suggests that atorvastatin therapy achieves a reduction in major cardiovascular events within the first year of therapy. Aside from obvious clinical benefits, economic advantage may also result from this observation. The present analysis modeled the clinical and economic consequences of initiating atorvastatin versus generic simvastatin in defined US managed care organization patient populations.
Research design and methods: A cost-consequence model was developed to estimate the differential rate and associated costs of cardiovascular events occurring over 2 years using real world price and adherence data. Four defined patient populations were included from representative atorvastatin trials: (1) diabetes mellitus; (2) multiple risk factors; (3) coronary heart disease; and (4) acute coronary syndrome. Costs of care included drug costs and costs of managing cardiovascular events. Univariate sensitivity analyses and multivariate sensitivity analysis via Monte Carlo simulation were conducted to test the robustness of the results.
Main outcome measures: The number of cardiovascular events avoided per 100,000 patients initiated on atorvastatin as compared with simvastatin, and total treatment costs.
Results: The model predicts that, relative to simvastatin, atorvastatin will prevent 941 (95% confidence interval [CI] 481-1367) cardiovascular events after 1 year and 1426 (95% CI 833-1987) events after 2 years, per 100,000 patients. This is expected to reduce the cost of cardiovascular events by $365 (95% CI $192-$527) and $552 (95% CI $327-$763) per patient (US$ 2006), respectively, offsetting 80% and 75% of the medication cost difference between atorvastatin and simvastatin after 1 and 2 years, respectively. The incremental costs associated with atorvastatin treatment were estimated at $94 (95% CI -$68 to $267) and $175 (95% CI -$37 to $399) per patient after 1 and 2 years, respectively. Results were sensitive to assumptions regarding simvastatin efficacy and drug acquisition costs.
Conclusions: Although the present analysis is based in part on indirect comparisons and on trials not designed or statistically powered to specifically test the early benefits hypothesis, it suggests that atorvastatin's assumed early reduction of cardiovascular events partly offsets the acquisition price difference between atorvastatin and generic simvastatin in various groups of high-risk patients newly initiated on statin treatment.