Heart failure, which affected 5.7 million Americans in 2012, is on the decline.

A new Mayo Clinic study tracking heart failure in Olmsted County residents found that rates of the condition plummeted 37.5 percent from 2000 to 2010. The nine-person research team, led by senior author Dr. Véronique Roger, published their findings in the most recent issue of "The Journal of the American Medical Association."

They did not study why the medical condition declined, though trends like less tobacco use, prescribing statins for patients and improving treatment of high blood pressure are "presumed" to be drivers of that trend, Roger said.

Recent research has found that heart attacks, an acute and often fatal event, were dropping. That led Roger and her colleagues to study if the number of patients with heart failure, a serious cardiac condition was also on the downswing.

While discovering that heart failure was dropping was not surprising, Roger said they were surprised by how steep the drop was.

"We expected it to decline, but we did not expect it would decline so much," she said.

The study tracked men and women in Olmsted County during those 10 years. It found heart failure cases dropped by 315.8 per 100,000 people in 2000 to just 219.3 cases in 2010.

This is, unequivocally, good news," Roger said.

The bad news is that the survival rate of the patients with heart failure did not improve in those 10 years.

"Once you get it, you're still in trouble," she said. "What we found is that people are not dying less and they are not less hospitalized less"

Their research did find that hospitalization and death of heart failure patients often wasn't actually from heart failure. There are other conditions "that travel with heart failure," like diabetes and arthritis, Roger said. Those other conditions and/or how the related medications interact can cause problems, often fatal ones, for heart failure patients.

That's a practical point that the researchers hope might improve treatment of heart failure patients.

"The message to care providers is to be mindful that heart failure is just one piece of the puzzle of people living with multiple chronic diseases. Patients have to be looked at as a whole, not just as a heart," she said.

How this Olmsted County-specific research applies to the rest of the county is a subject for debate within the medical community. In the same issue of JAMA, a doctor from Indianapolis, pointed out possible limitations of a such a localized study in an editorial titled "Heart Failure — An Epidemic or a Shifting Landscape?

"Although this population has been a great source of information on the classification, incidence, and prognosis of HF, generalization to other more diverse and underserved populations must be done with care," wrote Dr. Mary Norine Walsh. "The finding of a decline in HF incidence in Olmsted County may reflect changes in care patterns unique to that region."

Walsh points out that the Olmsted County population is predominantly white, highly educated with higher than average incomes plus 95 percent have health insurance.

Roger disagrees with that position, because data from many previous such research papers have matched larger trends.

"We have ample data on other forms of chronic disease that shows what happens in Olmsted County is completely parallel to what happens in the upper Midwest, to the State of Minnesota and most similar populations in the U.S.," he said. "What we do here is highly relevant to what's happening in the nation."

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