Background: Atherosclerosis is a condition in which fats, cholesterol, fibrin, and other substances accumulate into plaque on the arterial walls. Plaque can harden and narrow the arteries, in turn limiting the blood flow and resulting in diseases, such as acute myocardial infarction (AMI), ischemic stroke (IS), or peripheral arterial disease (PAD). There is a fairly high risk of a secondary atherosclerotic event if patients are not treated after the primary episode.Objective: To calculate the statistical probability of developing AMI, IS, or PAD after treating the primary disease.Methods: Data for statistical probability studies included 507,690 patients with primary atherosclerotic disease, who were in treatment during the study period and who did or did not develop a secondary atherosclerotic disease event.Result: Statistical probability data indicate that few AMI patients can develop IS (2.99%) or PAD (2.86%) as a secondary disease. Patients with primary diagnoses of IS showed a 5.07% risk of developing PAD and a 0.95% risk of developing AMI; however, PAD patients showed a higher probability for both AMI (9.17%) and IS (8.79%). Conclusion:Secondary atherosclerotic disease episodes after IS, AMI, and PAD were confirmed by statistical probability and are consistent with data from the literature. The study revealed that a primary PAD event leads to high rates of secondary episodes, and special attention should be given to the diagnosis and treatment of PAD in order to decrease the occurrence of secondary events.