The incidence rate for heart failure dropped steeply over a decade in a population-based study, and while hospitalization rates remained steady over time, causes shifted from cardiovascular to noncardiovascular.

Researchers at the Mayo Clinic in Rochester, Minn., frequently use Olmsted County in their state for epidemiological studies because medical care for the most part is provided through the Mayo system. That gives them access to most medical records from both inpatient and outpatient sources. In this study, Yariv Gerber, PhD, and colleagues tracked heart failure incidence in the county between 2000 and 2010 and outcomes at a mean 4.5 years of follow-up. The analysis broke heart failure into two groups: preserved (ejection fraction of 50 percent or greater) and reduced (less than 50 percent).  

They identified 2,762 incident heart failure cases over the decade. In that period, heart failure with preserved ejection fraction accounted for an increasing proportion of cases, from 47.8 percent in 2000-2003 to 52.3 percent from 2008-2010.

Incidence rates changed from 315.8 per 100,000 in 2000 to 219.3 per 100,000 in 2010, with a mean annual decline of 4.6 percent and an overall decrease of 37.5 percent. Women showed a greater decline than men, and their rates of heart failure with reduced ejection fraction fell faster than for preserved ejection fraction.

Gerber et al had follow-up data on 2,644 patients. They calculated a mortality rate in this group of 20.2 percent at one year after diagnosis and 52.6 percent at five years. Mortality rates increased with age, and 54.3 percent of deaths were deemed from noncardiovascular causes.

At two years, this group accounted for 4,631 hospitalizations (1.34 per person-year), and 63 percent of those were due to noncardiovascular causes.

‘[D]isease-specific interventions cannot be expected to reduce all hospitalizations appreciably among persons living with [heart failure] given the high prevalence of comorbidity in these patients,” they wrote. “Our results support this hypothesis because cardiovascular hospitalizations declined over time among [heart failure with reduced ejection fraction] cases; however, overall hospitalization rates did not decline, and noncardiovascular hospitalizations even increased.”

The Olmsted County population is primarily white and higher income and may not represent other patient populations or demographics. The researchers proposed that, nonetheless, their results support care strategies and guidelines for heart failure that are more holistic than disease-centric.

The study was published online April 20 in JAMA Internal Medicine.