Professor Kamlesh Khunti, a GP and professor of primary care diabetes and vascular medicine at the University of Leicester, and colleagues studied 513 people given education about type-2 diabetes.
Patients received a one-off session of six hours' education about the condition within six weeks of initial diagnosis.
After one year, those given structured education showed benefits in terms of weight loss, smoking cessation and understanding of diabetes.
Three years after the programme, these patients had lower coronary heart disease risk scores and had greater understanding of the condition.
Differences in clinical measures also suggested a benefit of patient education after three years, but these were not statistically significant, the researchers found.
Editor's blog: Diabetes clinicians as diabetes patients