The rate of hospitalization for heart failure in the United States declined approximately 30% between 1998 and 2008, according to a report in the Oct. 19 issue of JAMA.
This decrease is especially "remarkable" in light of the finding that survival after HF hospitalization also rose slightly at the same time, which means that there likely were more repeat hospitalizations for HF in any given year, said Dr. Jersey Chen of Yale University, New Haven, Conn., and his associates.
The researchers performed "the largest study to date examining trends in HF hospitalization rates across the United States" by analyzing a sample of 320,618,412 Medicare fee-for-service claims during that decade.
The overall risk-adjusted hospitalization rate decreased from 2,845 per 100,000 person-years to 2,007 per 100,000 person-years, a relative decline of 29.5%. In addition, the number of unique patients hospitalized at least once for HF in a given year dropped from 2,014 to 1,462 per 100,000 person-years.
This decrease represents an estimated savings of $4.1 billion in Medicare costs, the investigators said (JAMA 2011;306:1669-78).
Declines in HF hospitalization occurred across all age, sex, and race categories, although the amount of the decrease varied among these groups. For example, black men showed the lowest rate of decline among all categories of race and sex.
In addition, hospitalization for HF varied widely among the states. In 16 states, the decrease was significantly greater than the overall national decrease, while the decrease was significantly smaller in three states.
Dr. Chen and his colleagues also calculated 1-year mortality after HF hospitalization. Overall, this rate, adjusted for patient age, sex, race, and comorbidity, declined from 31.7% to 29.6%, a relative decrease of 6.6%.
The researchers characterized this reduction in HF mortality as "modest."
As with the hospitalization rates, the mortality rates varied substantially by state. Four states showed a more significant drop than the national average, and five showed a significant increase during the study period.
Such decreases were not found in previous studies of earlier time periods, such as the Framingham Heart Study, which examined trends in 1970-1999, and an Olmsted County (Minn.) study, which assessed trends in 1979-2004. "Our results may differ from these earlier studies because HF hospitalizations may have started to decline only recently," Dr. Chen and his associates noted.
Several more recent studies have indicated that HF hospitalization rates began to decline in the 1990s in Sweden, Scotland, Australia, and New Zealand, they added.
As an observational cohort study, this study was unable to determine the reasons for the marked decline in HF hospitalization and the more modest decline in HF mortality. However, the investigators speculated that improvements in underlying coronary artery disease, myocardial salvage after MI, and blood pressure control all may have played a role.
Improvements in secondary prevention also likely reduced HF exacerbations leading to hospitalization, including greater use of beta-blockers, ACE inhibitors, and angiotensin receptor blockers. In addition, clinical practice patterns may have changed, favoring outpatient rather than inpatient management of HF.
This study was limited in that it included only Medicare patients. "Trends in HF hospitalization and mortality may differ in younger patients with different types of insurance," Dr. Chen and his associates said.
The study was supported by the Agency for Healthcare Research and Quality and the National Heart, Lung, and Blood Institute. Dr. Chen’s associates reported ties to United Healthcare and Medtronic.