Many individuals with atherosclerotic cardiovascular disease (ASCVD) remain untreated despite the recommendation of clinical guidelines that statins should be used. For a study, researchers sought to determine the effect of statin therapy on recurring major adverse cardiovascular events (MACE). The study utilized medical information and insurance claims from 4 U.S. health care systems. Adults who survived an ASCVD hospitalization from September 2013 to September 2014 and met the inclusion criteria were followed for 1 year. A multivariable extended Cox model was used to assess the outcome of time-to-first MACE, followed by a multivariable joint, marginal model to examine the relationship between post-index statin use and nonfatal and fatal MACE. The study included 8,168 participants; 3,866 filled a statin prescription ≤90 days before the index ASCVD occurrence (47.33%), and 4,152 filled a statin prescription after the index ASCVD event (50.83%). These post-index users of statins were younger and had higher co-morbidities. About 686 (8.4%) patients experienced 763 occurrences (315/763, 41.3% terminal). The adjusted overall MACE risk decrease was 18% (HR 0.82, 95% CI 0.70 to 0.95, P=0.007), with a greater reduction in the first 180 days (HR 0.72, 95% CI 0.60 to 0.86, P<0.001). There was a nonsignificant 19% reduction in the number of nonfatal MACE (rate ratio 0.81, 95% CI 0.49 to 1.32, P=0.394) and a 65% reduction in the risk of mortality from any cause (HR 0.35, 95% CI 0.22 to 0.56, P<0.001). Investigators identified a slight increase in statin use following an ASCVD incident, with nearly half of the patients remaining untreated. The primary advantage of using statins was protection against premature death. Statin use had the strongest influence in the first 6 months following an ASCVD occurrence; consequently, patients must adhere to this medication as soon as possible.