The relationship between diabetes and cardiovascular events such as heart attacks and strokes has changed significantly in the last two decades, according to new data published in JAMA.[1] Improvements in patient care appear to be the primary driver of this particular trend.
“Between 1982 and 2000, people with diabetes had the same risk of cardiovascular events as those with prior cardiovascular disease (CVD),” wrote lead author Calvin Ke, MD, PhD, an assistant professor with the department of medicine at the University of Toronto, and colleagues. “Consequently, diabetes is considered a ‘cardiovascular risk equivalent.’ Because diabetes management practices have changed substantially, we examined secular trends in the association of diabetes and prior CVD with cardiovascular events from 1994 to 2019 to see whether the risk equivalence persists.”
Ke et al. examined administrative healthcare data from Ontario, Canada, focusing on adult patients who were living there in 1994, 1999, 2004, 2009 and 2014. Each patient was followed up for up to five years. Patients who did not present with diabetes or CVD stood as the study’s reference group.
The mean patient age was 44.4 years old when looking at 1994 data, but 47.5 years old when focused on 2014, an increase researchers said reflected the area’s aging population. For this study, “cardiovascular events” were defined as hospitalizations due to acute myocardial infarction, hospitalizations due to stroke and all-cause mortality.
Overall, the team found that diabetes and prior CVD were both associated with “an increased risk of cardiovascular events” among patients from the 1994 cohort. The rate of cardiovascular events was 28.4 per 1,000 person-years among patients with diabetes, 36.1 per 1,000 person-years among patients with prior CVD and 12.7 per 1,000 person-years among patients without diabetes or prior CVD.
The risk was highest, as one might expect, when a patient presented with both diabetes and prior CVD (74 per 1,000 person-years).
Examining the 2014 cohort, however, the researchers noted that things had changed considerably. The rate of cardiovascular events among patients without diabetes or prior CVD, for example, had dropped all the way to 8 per 1,000 person-years. Also, the rate of cardiovascular events among patients with diabetes was down to 14 per 1,000 person-years, a decrease of more than 50%.
The rate of cardiovascular events among patients with prior CVD, meanwhile, was 23.9 per 1,000 person-years in 2014. A history of diabetes and CVD was still associated with the highest risk; the rate was 51.3 per 1,000 person-years for that patient population.
“In this large, population-based study, the magnitude of the association between diabetes and risk of cardiovascular events decreased, while that between CVD and such events remained stable,” the authors wrote. “These results suggest that diabetes is still an important cardiovascular risk factor but no longer equivalent to CVD—a change that likely reflects the use of modern, multifactorial approaches to diabetes.”
The authors did note that their study had certain limitations, including its lack of data on specific risk factors and cause-specific mortality. Also, while their analysis does capture improved risks among patients in 2014 compared to 1994, they concluded that “better prevention and optimal management of diabetes and CVD remain essential.”
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.