PRIORITIZING INDIVIDUALS FOR PREVENTIVE STATIN THERAPY: BEYOND TEN-YEAR RISK

Purpose:

Individuals are presently prioritized for preventive statin therapy based on their ten-year risk of experiencing a primary cardiovascular event. In Scotland, the risk threshold for statin eligibility is 20%. As this risk threshold applies to all individuals regardless of other risk factors it is referred to as the blanket risk threshold approach. Age is a dominant risk factor for cardiovascular disease (CVD) and consequently a disproportionate number of older individuals are prescribed statins. Recent literature has shown that younger individuals have the greatest capacity to benefit from statin therapy. This research compares the population-level outcomes associated with alternative approaches to statin prioritization, namely the age-differentiated risk threshold and lifetime benefit approaches.

 

Method:

The Scottish CVD Policy Model (SCVDPM), a previously published decision-analytic model, was used to assess the health and cost outcomes associated with different approaches to statin prioritization. The SCVDPM is a Markov-type model which employs parametric competing risk analysis to predict life expectancy, quality-adjusted life expectancy, and cost outcomes for individuals based on their CVD risk factor information. One-way sensitivity analysis was performed to assess uncertainty around key modelling assumptions.

 

Result:

NHS Scotland could achieve significant life year gains while prescribing statins to the same number of people as at present if it were to change the way in which CVD-free individuals are prioritized for statin therapy. The incremental cost-effectiveness ratio (ICER) associated with reducing the blanket risk threshold to 10% was £4,500/QALY. The ICER associated with implementing the age-differentiated risk threshold approach was £7,400/QALY. The ICER associated with implementing the lifetime benefit approach was £23,300/QALY. Results were sensitive to statin efficacy in intermediate risk groups and the level of treatment-related side effects.

 

Conclusion:

The 20% blanket risk threshold approach is not the most cost-effective means of prioritising individuals for preventive statin therapy. Depending on a decision-maker's cost-effectiveness threshold, the 10% blanket risk threshold, age-differentiated risk threshold, or lifetime benefit approach should be pursued. The cost-effectiveness frontier containing these policies is shown in Figure 1. Alternative approaches to statin prioritization may also increase physician and patient adherence to guidelines and further research should include value of implementation analysis.