Location Linked to Incidence of Cardiovascular Events

Where an individual is located may help determine their risk of heart attack, stroke, or dying of cardiovascular disease, according to a study published in theCanadian Medical Association Journal.

For the study, investigators examined regional variations within Ontario, Canada’s 14 Local Health Integration Networks (LHINs). The regions were divided into the following 3 categories: LHINs with the lowest number of cardiovascular events (3.2 to 3.5 events per 1000 person-years); medium cardiovascular events (3.9 to 4.7 events per 1000 person-years); and highest (4.8 to 5.7 events per 1000 person-years).

The investigators examined approximately 5.5 million adults aged 40 to 79 years—–as of January 1, 2008––in Ontario with no previous cardiovascular disease. The patients were followed for 5 years as investigators looked for heart attacks, strokes, or cardiovascular-related deaths.

LHINs with the lowest number of events (Central, Mississauga Halton, and Toronto Central) were located in the highly populated Greater Toronto Area. Individuals who resided in these regions visited their primary care physicians more often and were more likely to be screened for heart disease risk factors. They also had better control of high blood pressure compared with residents of higher event areas.

The LHINs with the highest event rates were found in northern Ontario with the lowest population density (North East LHIN and North West LHIN), as well as the North Simcoe Musckoka LHIN and Erie St Clair LHIN. Individuals who lived in these regions were more likely to be obese, to smoke, and to have the lowest dietary intake of fruits and vegetables.

“What we found was a striking variation in the rates of heart attack, stroke, or cardiovascular-related death depending on which LHIN a person lived in,” said lead author Dr Jack Tu. “There was a clear division between the healthiest and the least healthy LHINs.”

Based on the findings, the authors suggest that improving access to preventive care in regions with high rates of cardiovascular events may help improve health outcomes.

“Our study suggests that, even in a country with a universal health insurance system, higher rates of preventive health care contribute to lower rates of CVD [cardiovascular disease] events at a regional level,” the authors wrote. “Our findings provide new information that health system factors may be important contributors to regional variations in CVD event rates.”

The study was conducted by the Cardiovascular Health in Ambulatory Care Research Team, a big data initiative designed to improve heart health and quality of outpatient care in Ontario, Canada.

In a related commentary, Dr Genevieve Gabb from the Royal Adelaide Hospital and University of Adelaide, Australia, wrote that regional variation in heart disease incidence is also seen in other countries, including Australia.

“The solution to reducing variations in geographic incidence of primary cardiac events will not be found solely in addressing health service factors,” Dr Gabb wrote. “Consideration of public health measures and addressing inequalities in social determinants of health are also essential. Disease burden should be considered when determining resource allocation.”