The number of people at risk of heart disease has been underestimated because of outdated methods, scientists claim.
The researchers' study took place over a 10-year period
Researchers at Glasgow and Bristol universities said the current method of predicting risk uses old figures that do not include high-poverty areas.
Their 10-year study showed that manual workers in deprived areas were less likely to receive preventative care.
The scientists' findings were published in the British Journal of General Practice on Friday.
The research involved a decade-long study of 12,304 men and women from Renfrew and Paisley who were not suffering from a pre-existing cardiovascular disease.
Report author Dr Peter Brindle, of the University of Bristol, said: "Our results suggest that 4,196 people in the study, mainly from manual social classes, might have received preventative treatment had the scoring method been properly calibrated for this high-risk population.
"In fact, only 585 were eligible for treatment, leaving 3,611 people untreated."
Scientists found 696 of the people died from the condition, but only 406 of the deaths were predicted through the US-based Framingham risk scoring system, which is used to identify high-risk patients who should get preventative treatment.
Dr Brindle said the scoring system used an original study that did not include areas with high poverty levels and the higher health risks associated with these areas.
This meant deaths from heart disease were underestimated across the population as a whole.
He said that for people in manual occupations the risk was underestimated by 48%, compared to 31% for people in non-manual work.
People living in deprived areas were also less likely to receive cholesterol and blood pressure-lowering treatment, he said.
There has been a greater focus on the effects of poverty
Scotland's Health Minister, Andy Kerr, said: "This research backs up what we know already - much more needs to be done to help people in deprived areas improve their health.
"Having robust analysis to underpin our work is vital. We have been working on it already and we commissioned a study by the University of Dundee which was published recently.
"Like this latest study, it showed deprivation has not until now been included in most risk factor models. "
On Thursday, Mr Kerr annnouced a 10-year health plan for Scotland with a stronger focus on preventative medicine.
He said: "I want to see the health service getting out into the areas with the worst health records and doing much more preventative work to stop health problems before they occur."