A growing number of heart attack patients don’t have any standard risk factors

Risk factors such as high blood pressure, high cholesterol, being diabetic, or cigarette smoking, have long been used as predictors of developing heart disease.

However, a recent study by Heart Research Australia’s Professor Gemma Figtree, published in the European Journal of Preventive Cardiology, has found that there is an increasing proportion of heart attack patients without any standard risk factors, such as high cholesterol.

In Prof Figtree’s study, conducted from January 2006 to December 2014 at Royal North Shore Hospital, of the 695 patients who were treated for heart attack, 132 had no known risk factors.

The proportion of heart attack patients who had no risk factors in 2006 was 11%, and over the study period, increased to 27% by 2014.

“These results will have important implications for the need to both identify new triggers for heart disease and to better understand the outcomes and best management approach for this group of people,” says Prof Figtree.

The cause for this increase in proportion isn’t clear. Despite age mortality rates in Australia decreasing between 1979 and 2009, by 71% for males and 68% for females, coronary heart disease continues to cause a significant burden of disease and remains the leading cause of death in Australia.

“It may be that identification and treatment of standard risk factors like high blood pressure has been successful enough that patients without these treatable conditions are making up a greater proportion of patients having heart attacks,” Prof Figtree says.

“We did find that once these patients have a heart attack, how well they do, for example in terms of risk of dying, is the same as patients with standard risk factors, so it’s just as important that we try to prevent heart attacks in this group.

“The next step is to identify new ways of diagnosing heart disease to enable early identification and treatment of these patients to better protect them,” she says.

This study was supported by Heart Research Australia and Sydney University and took place at Royal North Shore Hospital, Sydney.