One in 10 Canadians have problems affording their prescription medication, often because they don't have insurance to help pay the costs, a new study has found.

The study, which appears in the Canadian Medical Association Journal, found that for Canadians without drug plans through work or private drug insurance, one in four cannot afford their medications.

The findings come from a review of a 2007 Statistics Canada survey, called the Canada Community Health Survey.

Researchers from the University of British Columbia and the University of Toronto found that among the 5,700 respondents who said they had been given a prescription for a medication, 9.6 per cent had either not filled the prescription for cost reasons, or deliberately skipped doses to save money.

More than 26 per cent of those who did not have drug insurance reported not being able to afford to pay for their prescription drugs. That compares to only 6.8 per cent of those who did have drug insurance.

In all, people without drug insurance were 4.5 times more likely to avoid taking prescribed medications because of cost.

Perhaps not surprisingly, having a low income increased the likelihood that patients hadn't taken a prescribed medication. Canadians with low incomes were 3.3 times more likely not to take their prescription drugs because they could not afford them.

Canadians who reported fair or poor health status did not take their prescribed medications 2.6 times more often than those who reported good or excellent health. As well, those with chronic conditions were 1.6 times more likely to not take their medicines as directed because of cost.

Patients in British Columbia were most likely to say they didn't take their prescribed medications because of the cost. That finding surprised the authors, who said it might result from B.C.'s high-deductible public drug plan or the high level of personal debt among B.C. residents.

"The findings of our study are really troubling," says one of the study's authors, Dr. Michael Law, of the Centre for Health Services and Policy Research at the University of British Columbia.

"We claim to have a universal system and we have that for hospitals and physicians. But in Canada, we can't claim to have a universal health care system if one in 10 are reporting they can't afford their prescription drugs."

Law notes that more is spent on prescription drugs in Canada than on doctors and that it makes no sense that says prescription medications are not included in the country's medicare system.

Law and the other study authors point out that when patients are unable to afford their medications, it can lead to higher costs down the road for the health care system.

"Reducing cost-related non-adherence would likely improve health and reduce spending in other areas, such as admissions to hospital for acute care," they write.

"As drug costs continue to increase I think we will see more and more people will fall into the category of not being able to afford to take their drugs as directed," he said.

Dr. Danielle Martin, chair of Canadian Doctors for Medicare says her group believes that all prescription medications should be included in the Canada Health Act.

"It is time Canada treated prescription drugs like the lifesaving interventions they are," she said in a statement.

Martin says studies have shown that paying for medications can lead to cost savings down the line.

She points to a recent study in the New England Journal of Medicine which found that providing free medications to heart attack patients actually helped save money.

Even though the medications were free, the costs to the insurer did not increase because patients who regularly took their medications were hospitalized less often.

"The evidence shows that providing prescription drugs for free in many situations is not only the right thing to do, but it also makes economic sense," said Martin.

Dr. Law says his team's findings are timely given that the premiers are meeting this week to discuss health care.

"As the provincial premiers meet in Victoria this week, they should consider expanding and improving public coverage for prescription drugs to reduce the influence of cost on whether or not Canadians can afford their prescription drugs," he said in a statement.

With files from CTV's medical specialist Avis Favaro and producer Elizabeth St. Philip