TORONTO -- A study that looked at the number of new cases of heart failures in Ontario over a decade suggests the rates of incidence have dropped significantly.

The study, published Monday in the Canadian Medical Journal, found a 32.7 per cent decline in the number of patients diagnosed with heart failure in Ontario between 1997 and 2008.

That's an average annual decline of three per cent.

Dr. Jack Tu, of Sunnybrook Health Sciences Centre, says the drop is in line with declines recently observed across Canada and in other countries.

The study does not directly attribute specific reasons for the decline, but Tu says drops in smoking rates and better hypertension control are likely factors that have affected the number of new cases in Ontario.

Older patients, particularly those over the age of 85, showed the greatest decline among all age groups, but the study cautions that younger people are the ones who will determine future trends.

"Younger Canadians are the generation most at risk now," said Tu, the study's senior author.

He cautioned that the study's findings are not all that rosy.

"It's a mixture of good news and bad news," he said in an interview.

"The good news is the frequency of heart failure is declining significantly. The bad news is, for those who do develop heart failure, the prognosis is still quite poor."

That's because in addition to the reduction in overall incidence of heart failure, the study showed only a marginal improvement in readmission numbers as well deaths following a heart failure diagnosis.

"We still need to improve survival rates," said Tu.

Researchers from University of Toronto, University Health Network and the Schulich Heart Centre contributed to the study that looked into 419,551 cases of heart failure in Ontario between April 1997 and March 2008.

The data came from the Ontario Health Insurance Plan (OHIP) database.

"What the study adds is that we show that (in) outpatients, the incidence of heart failure is also declining at similar rates as hospitalized patients," says Tu.

"There really is a decline that's not just in hospital settings."