Patients with low medication adherence had a 27 percent higher rate of major cardiovascular events compared with those who consistently took their medication. Until now, researchers have found it difficult to determine how long-term adherence to diabetes medication affects the risk of heart attack, stroke and other major cardiovascular events. Even after these adjustments, people who were less adherent to diabetes medication remained at higher risk of developing cardiovascular disease. The researchers noted that the study is observational, meaning it cannot prove that poor medication adherence directly causes cardiovascular disease. About the researchBecause the study is an observational study, the researchers cannot prove that poor medication adherence directly causes heart disease.