Cost-effectiveness of high, moderate and low-dose statins in the prevention of vascular events in the Brazilian public health system

Abstract

Background: Statins have proven efficacy in the reduction of cardiovascular events, but the financial impact of its widespread use can be substantial.

Objective: To conduct a cost-effectiveness analysis of three statin dosing schemes in the Brazilian Unified National Health System (SUS) perspective.

Methods: We developed a Markov model to evaluate the incremental cost-effectiveness ratios (ICERs) of low, intermediate and high intensity dose regimens in secondary and four primary scenarios (5%, 10%, 15% and 20% ten-year risk) of prevention of cardiovascular events. Regimens with expected low-density lipoprotein cholesterol reduction below 30% (e.g. simvastatin 10mg) were considered as low dose; between 30-40%, (atorvastatin 10mg, simvastatin 40 mg), intermediate dose; and above 40% (atorvastatin 20-80 mg, rosuvastatin 20mg), high-dose statins. Effectiveness data were obtained from a systematic review with 136,000 patients. National data were used to estimate utilities and costs (expressed as International Dollars - Int$). A willingness-to-pay (WTP) threshold equal to the Brazilian gross domestic product per capita (circa Int$11,770) was applied.

Results: Low dose was dominated by extension in the primary prevention scenarios. In the five scenarios, the ICER of intermediate dose was below Int$10,000 per QALY. The ICER of the high versus intermediate dose comparison was above Int$27,000 per QALY in all scenarios. In the cost-effectiveness acceptability curves, intermediate dose had a probability above 50% of being cost-effective with ICERs between Int$ 9,000-20,000 per QALY in all scenarios.

Conclusions: Considering a reasonable WTP threshold, intermediate dose statin therapy is economically attractive, and should be a priority intervention in prevention of cardiovascular events in Brazil.

Figure 1

Schematic representation of the cost-effectiveness models. * If a patient in the post-stroke state had a diagnosis of stable angina, he would remain in the same state, but with a tracker variable signaling the angina diagnosis. § The structure of the secondary prevention model was similar, with the exception of the "No previous CVD” Markov state, which was omitted. CV: cardiovascular; CVD: cardiovascular disease; MI: myocardial infarction; SA: stable angina.

Figure 2

Cost-effectiveness acceptability curves of the five base-case scenarios (secondary and primary prevention, with ten-year risks ranging between 5% and 20% in the latter) and of the 5% ten-year risk primary prevention alternative scenario with statin prices fixed at the retail sales prices of the drugs.

Figure 3

Cost-effectiveness acceptability curves of alternative scenarios (secondary prevention and 10% to 20% ten-year risk primary prevention), where statin prices were fixed at the retail sales prices of the drugs. The curves show the probabilities that the various statin doses would be cost-effective at varying threshold costeffectiveness values.