Cost-effectiveness of 10-Year Risk Thresholds for Initiation of Statin Therapy for Primary Prevention of Cardiovascular Disease

Abstract

Importance: The American College of Cardiology and the American Heart Association (ACC/AHA) cholesterol treatment guidelines have wide-scale implications for treating adults without history of atherosclerotic cardiovascular disease (ASCVD) with statins.

Objective: To estimate the cost-effectiveness of various 10-year ASCVD risk thresholds that could be used in the ACC/AHA cholesterol treatment guidelines.

Design, setting, and participants: Microsimulation model, including lifetime time horizon, US societal perspective, 3% discount rate for costs, and health outcomes. In the model, hypothetical individuals from a representative US population aged 40 to 75 years received statin treatment, experienced ASCVD events, and died from ASCVD-related or non-ASCVD-related causes based on ASCVD natural history and statin treatment parameters. Data sources for model parameters included National Health and Nutrition Examination Surveys, large clinical trials and meta-analyses for statin benefits and treatment, and other published sources.

Main outcomes and measures: Estimated ASCVD events prevented and incremental costs per quality-adjusted life-year (QALY) gained.

Results: In the base-case scenario, the current ASCVD threshold of 7.5% or higher, which was estimated to be associated with 48% of adults treated with statins, had an incremental cost-effectiveness ratio (ICER) of $37,000/QALY compared with a 10% or higher threshold. More lenient ASCVD thresholds of 4.0% or higher (61% of adults treated) and 3.0% or higher (67% of adults treated) had ICERs of $81,000/QALY and $140,000/QALY, respectively. Shifting from a 7.5% or higher ASCVD risk threshold to a 3.0% or higher ASCVD risk threshold was estimated to be associated with an additional 161,560 cardiovascular disease events averted. Cost-effectiveness results were sensitive to changes in the disutility associated with taking a pill daily, statin price, and the risk of statin-induced diabetes. In probabilistic sensitivity analysis, there was a higher than 93% chance that the optimal ASCVD threshold was 5.0% or lower using a cost-effectiveness threshold of $100,000/QALY.

Conclusions and relevance: In this microsimulation model of US adults aged 45 to 75 years [corrected], the current 10-year ASCVD risk threshold (≥7.5% risk threshold) used in the ACC/AHA cholesterol treatment guidelines has an acceptable cost-effectiveness profile (ICER, $37,000/QALY), but more lenient ASCVD thresholds would be optimal using cost-effectiveness thresholds of $100,000/QALY (≥4.0% risk threshold) or $150,000/QALY (≥3.0% risk threshold). The optimal ASCVD threshold was sensitive to patient preferences for taking a pill daily, changes to statin price, and the risk of statin-induced diabetes.

Figure 1. One-Way Sensitivity Analysis Showing the Optimal ASCVD Threshold as a function of Statin Price

ASCVD indicates atherosclerotic cardiovascular disease; QALY, quality-adjusted life-years. The optimal treatment threshold (using a cost-effectiveness threshold of $100 000/QALY) changes from ≥3.0% to ≥10.0% as statin price increases from $150/y to $1000/y (base-case value is $268/y). Optimal strategies are also shown for cost-effectiveness thresholds of $50 000/QALY and $150 000/QALY. No ASCVD treatment threshold was cost-effective for statin prices greater than $500/y using a cost-effectiveness threshold of $50 000/QALY. No ASCVD treatment threshold was cost-effective for statin prices greater than $1000/y using a cost-effectiveness threshold of $100 000/QALY.

Figure 2. Cost-effectiveness Acceptability Curves for the Probabilistic Sensitivity Analysis

ASCVD indicates atherosclerotic cardiovascular disease. The y-axis shows the likelihood that strategies would be considered cost-effective for a given cost-effectiveness (willingness-to-pay) threshold. Panel A shows the probability of a given ASCVD threshold being optimal; the ASCVD treatment threshold of ≥30% and the treat all patients with statins strategies were not optimal in any probabilistic sensitivity analysis iterations. Panel B shows the probability that ASCVD thresholds of 7.5% or lower, 5.0% or lower, and 3.0% or lower were optimal.