ACC/AHA guidelines superior to ESC/EAS guidelines for primary prevention with statins in non-diabetic Europeans: the Copenhagen General Population Study

Mortensen MB, Nordestgaard BG, Afzal S, et al.
European Heart Journal 2016; published online ahead of print

Background

For primary prevention of ASCVD, not only public health initiatives are important, but also personalized prevention for those at the highest risk. These individuals at highest risk and who benefit from statins, are identified by risk prediction models proposed by the ACC/AHA guidelines, as well as the ESC/EAS guidelines for primary prevention of ASCVD. Both guidelines endorsing the principle of matching the intensity of preventive efforts with the absolute ASCVD risk of the individual.
However, both guidelines provide different risk prediction models, and different decision thresholds (any ASCVD in the US or fatal ASCVD in Europe) are recommended for statin therapy [1-4].

To elucidate which risk prediction model to prefer for optimal primary prevention of ASCVD, a head-to-head comparison of the clinical performance of the two guidelines was performed, using different risk prediction models (US pooled cohort equations [US-PCE] for any ASCVD and European systematic coronary risk evaluation system [European-SCORE] for fatal ASCVD) and different statin eligibility criteria (class I and IIa recommendations) in a large, population-based European cohort (44,889 individuals all free of ASCVD, diabetes and statin use at baseline).

Main results

• There were 10 and 14 times more ‘any ASCVD events’ than ‘fatal ASCVD events’ in men and women, respectively.
• Accuracy of match predicted events/observed events: The overall predicted-to-observed (P/O) event ratio was 1.2 using US-PCE for any ASCVD compared with 5.0 using European-SCORE for fatal ASCVD.
• The US-PCE was well calibrated around the guideline-defined decision thresholds for statin therapy of 7.5% and 5% (P/O ratio: 1.0–1.1), but slightly overestimated risk when the predicted risk was high (≥10%; P/O ratio: 1.4).
• The European-SCORE markedly overestimated risk across all categories and deciles of predicted risk, with overestimation around both the high-risk (5%; P/O ratio: 3.6) and very high-risk (10%; P/O ratio: 5.4) thresholds for statin therapy.
• US-PCE discriminated equally well or better than the European-SCORE between cases and non-cases, with c-statistics ranging from 0.71 to 0.85 for US-PCE compared with 0.69 to 0.84 for European-SCORE.
• For a Class I recommendation, 42% of individuals qualified for statins using the ACC/AHA guidelines vs. 6% with the ESC/EAS guidelines. All who qualified for statin therapy by the ESC/EAS guidelines did also qualify with the ACC/AHA guidelines. A similar difference between ACC/AHA and ESC/EAS guidelines was found for men and women separately, and for Class IIa recommendations.
• The ACC/AHA compared with ESC/EAS guidelines increased the eligibility for statin therapy both among those who developed any ASCVD (increase in sensitivity from 10% to 72%) and those who did not develop any ASCVD (decrease in specificity from 95% to 60%), resulting in a positive NRI of 0.27.
• The ACC/AHA compared with ESC/EAS guidelines increased the eligibility for statin therapy among those who developed fatal ASCVD (increase in sensitivity from 11% to 87%) and those who did not develop fatal ASCVD (decrease in specificity from 94% to 59%), resulting in a positive NRI of 0.40.
• The sensitivity and specificity of a US-PCE risk of 5% were similar to those of a European-SCORE risk of 1.4%, while a US-PCE risk of 7.5% was similar to a European-SCORE risk of 2.4%.

Conclusion

In a large European cohort, the ACC/AHA guidelines were superior for the primary prevention of ASCVD, by means of assigning statin therapy to those who would benefit the most, compared with the ESC/EAS guidelines. These data suggest that the US guidelines have favourable effects on ASCVD prevention compared with the European guidelines.

Find this article online at Eur Heart J

References

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