Patients with atherosclerotic cardiovascular disease (ASCVD) who took high-intensity statins had a one-year survival advantage compared with those who received moderate-intensity statins, according to a retrospective cohort analysis.

The study also found that maximal doses of high-intensity statins were associated with a greater survival benefit than submaximal high-intensity statins.

Lead researcher Fatima Rodriguez, MD, MPH, of Stanford University, and colleagues published their results online in JAMA Cardiology on Nov. 9.

“The greatest strength of this study is that we used a very large, well-defined clinical cohort,” Rodriguez said in a news release. “The results show that high-intensity statins confer a survival advantage for patients with cardiovascular disease, including older adults.”

The researchers noted that guidelines from the American College of Cardiology and American Heart Association recommends that patients who are 75 years old or younger and have ASCVD receive high-intensity statin therapy. They added that the guidelines define high-intensity statin therapy as 20 mg or 40 mg per day of rosuvastatin and 40 mg or 80 mg per day of atorvastatin. However, the guidelines do not suggest a specific dosage for patients with ASCVD.

For this analysis, the researchers evaluated data on 509,766 adults with ASCVD who were between 21 and 84 years old and were treated in the Veterans Affairs healthcare system from April 1, 2013, to April 1, 2014. They defined ASCVD as coronary artery disease, cerebrovascular disease or peripheral artery disease.

Patients were excluded if they had low-density lipoprotein levels of less than 50 mg/dL or more than 600 mg/dL and if they did not fill any prescriptions from a Veterans Affairs health system clinician during the six months before the index date. They were also excluded if they were currently receiving a moderate-intensity and previously were prescribed a higher-intensity statin in the previous five years.

The mean age of patients was 68.5 years old, and 98 percent were males. Of the patients, 29.6 percent received high-intensity statin therapy, 45.6 percent received moderate-intensity statin therapy, 6.7 percent received low-intensity statin therapy and 18.2 percent received no statin therapy.

The one-year mortality rates were 4.0 percent for patients receiving high-intensity statin therapy, 4.8 percent for patients receiving moderate-intensity statin therapy, 5.7 percent for patients receiving low-intensity therapy and 6.6 percent for patients receiving no statin therapy. During a mean follow-up period of 492 days, the patterns of survival were similar even after adjusting for the propensity to receive high-intensity statin therapy.

After adjustments, patients taking high-intensity statins had a 9 percent increased chance of survival compared with those taking moderate-intensity statins. Further, patients treated with maximal doses of statins had lower mortality compared with those treated with submaximal doses. The maximal doses were 80 mg of atorvastatin or 40 mg of rosuvastatin and the submaximal doses were 40 mg of atorvastatin, 20 mg of rosuvastatin and 80 mg of simvastatin.

The researchers found that the primary and secondary outcomes were similar for patients who were 75 years or younger and patients between 76 and 84 years old. In addition, patients receiving high-intensity statins were more likely to have a higher risk of acute MI but were less likely to have malignant neoplasms.

The researchers mentioned a few limitations of the study, including that they could not adjust for potential confounders and were unable to determine the cause of death. They also could not determine if patients received statins outside of the Veterans Affairs health system. In addition, they used medication possession ratios to determine adherence, but they could not determine if patients actually took the medications.

“These findings suggest there is a substantial opportunity for improvement in the secondary prevention of ASCVD through optimization of intensity of statin therapy,” the researchers wrote.