High-Potency Statin and Ezetimibe Use and Mortality in Survivors of an Acute Myocardial Infarction: A Population-Based Study

Study Questions:

What is the all-cause mortality in patients with a first acute myocardial infarction (AMI) who were treated with simvastatin, compared with a high-potency statin and simvastatin/ezetimibe combination?

Methods:

A retrospective longitudinal study was performed using the United Kingdom General Practice Research Database. Patients who had survived 30 days after their first AMI had not received prior statin or ezetimibe therapy and were started on a statin within 30 days of AMI were included. Three groups were identified according to their follow-up: 1) simvastatin monotherapy; 2) high-potency statin group (patients who started on simvastatin and switched to atorvastatin or rosuvastatin); and 3) ezetimibe/statin combination group (patients who received ezetimibe in addition to statin).

Results:

A total of 9,597 patients (57% male, mean age 65 ±13 years) matched study criteria: simvastatin (n = 6,990 [72.8%]); high-potency statin (n = 1,883 [19.6%]); and ezetimibe/statin combination (n = 724 [7.5%]). During a mean follow-up of 3.2 years, there were 1,134 (12%) deaths. In the multivariate proportional hazards model, the adjusted hazard ratio for high-potency statin and ezetimibe group was 0.72 (95% confidence interval [CI], 0.59-0.88; p < 0.001) and 0.96 (95% CI, 0.64-1.43; p = 0.85), respectively. A similar result was also obtained in the propensity score analysis that took into account covariates that predicted drug treatment groups.

Conclusions:

Patients switched to a high-potency statin had a significantly reduced mortality compared with simvastatin monotherapy. There was no observed mortality benefit in the ezetimibe group.

Perspective:

Because of the higher baseline total cholesterol levels, the best achieved total cholesterol levels were not lower in the high-potency statin and ezetimibe/statin combination groups. Most importantly, the ezetimibe/statin group was exceedingly small, limiting the power to determine the effect. The value of ezetimibe plus statins compared to simvastatin monotherapy will have to await the results of the IMPROVE-IT trial, which should be available next year.


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