New criteria would shift statin eligibility to more subjects at intermediate CV risk
Statin Eligibility in Primary Prevention: From a Risk-Based Strategy to a Personalized Approach Based on the Predicted Benefit
Introduction and methods
Current guidelines recommend statin prescription in primary prevention according to the calculated absolute risk of CVD . However, the treatment benefit depends also on the amount of LDL-c lowering, therefore, a benefit-based strategy for statin eligibility has been proposed, according to which, only individuals with an expected absolute risk reduction above a threshold would be candidates for statin therapy [2,3].
In this cross-sectional study, statin eligibility was assessed based on the predicted CV benefit, rather than the absolute CV risk, in a large database of individuals in primary prevention. Eligible for the study were 16,008 subjects aged 40-75 years, with LDL-c between 70 and 190 mg/dL, not on lipid-lowering drugs, who underwent a routine health screening in a single center.
The 10-year CV risk was calculated by the pooled cohort equations, according to the 2013 ACC/AHA guideline recommendation, and statin eligibility was defined as a 10-year CV risk ≥7.5% . The predicted number needed to treat (NNT) to prevent one major CV event over 10 years (NNT10) was calculated as the reciprocal of the expected absolute risk reduction. The NNT10 threshold that resulted in the same number of statin candidates as in the risk-based approach, was called equivalent NNT10.
- Based on the absolute CV risk method, 14% of the study population was eligible for statin therapy. The same number of statin candidates would be achieved by selecting those with a predicted absolute risk reduction in 10 years of at least 2.2% with a 40% LDL-c reduction (NNT10 <45).
- In the risk-based strategy, the minimal predicted absolute risk reduction in 10 years would be 1.3%, corresponding to a NNT10 of 76. If this NNT10 was selected as the threshold in a benefit-based strategy, statin eligibility in the study population would increase to 27%.
- Compared to individuals who would become statin ineligible, 11% of individuals considered statin eligible using the risk-based strategy would be replaced by younger individuals (56.3 ± 5.6 years vs 51.5 ± 4.7 years; P <0.01), with higher LDL-c levels (101 ± 16 mg/dL vs 166 ± 13 mg/dL; P <0.01) and a lower calculated 10-year CV risk (8.5 ± 1.0% vs 6.9 ± 0.4%; P <0.01), if the NNT-based approach was used (equivalent NNT10 of 45 as the threshold, assuming 40% LDL-c reduction).
- The NNT-based strategy increases statin eligibility in patients at intermediate CV risk (10-year CV risk between 5.0% and <10.0%), without a major impact on the estimated 10-year CV risk in the overall study population.
- These modifications in statin eligibility would translate into a modestly enhanced CV benefit in the subgroup with baseline CV risk between 5.0% and <7.5%, and loss of benefit in the subgroup with risk between 7.5% and <10.0%, compared with the risk-based strategy.
Defining statin eligibility based on the predicted CV benefit, rather than the absolute CV risk, shifts statin eligibility to more intermediate CV risk subjects, without changing the overall rate of statin use in the population.