New York, Feb 17 (IANS): Most "risk calculators" used to gauge a patient's chances of suffering a heart attack significantly overestimate the likelihood of a heart attack, warns a study.

Four out of five widely used clinical calculators considerably overrate risk, including the most recent one unveiled in 2013 by the American Heart Association and the American College of Cardiology, as per the findings.

Physicians commonly use standardized risk assessment systems, or algorithms, to decide whether someone needs care with daily aspirin and cholesterol-lowering drugs or just watchful waiting and follow-up exams.

These algorithms calculate heart attack probability using a combination of factors, such as gender, age, smoking history, cholesterol levels, blood pressure and diabetes among others.

"Our results reveal a lack of predictive accuracy in risk calculators and highlight an urgent need to re-examine and fine-tune our existing risk assessment techniques," said senior investigator Michael Blaha from Johns Hopkins University.

For the study, the researchers followed 4,200 participants, ages 50 to 74, for over a decade.

The findings underscore the perils of over-reliance on standardised algorithms and highlight the importance of individualised risk assessment that includes additional variables, such as other medical conditions, family history of early heart disease, level of physical activity, its presence and amount of calcium buildup in the heart's vessels, the researchers said.

The study appeared in the Annals of Internal Medicine.