Heart Failure-Associated Hospitalizations in the United States

Study Questions:

What are the trends in heart failure (HF) hospitalizations within the United States?


HF hospitalizations between 2001 and 2009 were obtained from the Nationwide Inpatient Sample, the largest all-payer database in the United States. Using ICD-9 discharge coding, rates of primary and secondary HF hospitalizations with age- and sex-standardization were calculated using direct standardization methods.


Hospitalizations for HF (primary and secondary diagnoses) increased from 3,891,737 in 2001 to 4,244,865 in 2009. The mean age of hospitalized patients with HF dropped from 74.2 to 73.1 years, and most patients were Caucasian females with Medicare as the primary payer. Of the hospitalizations, 26.9% coded HF as the primary diagnosis, and 73% coded HF as secondary. From 2001-2009, there was a reduction (from 1,137,944 to 1,086,685) in hospitalizations with HF coded as the primary diagnosis (2.8% [1.7-3.8%] rate of decline). Age- and sex-adjusted primary HF hospitalization decreased from 566 to 468 per 100,000 people. From 2001-2006, there was an increase (from 1,370 to 1,476 per 100,000 people) in hospitalizations coding HF as a secondary diagnosis. Associated primary diagnoses included pulmonary disease (16%), renal failure, and infection. After 2006, HF hospitalizations as a secondary diagnosis then decreased to 1,359 per 100,000. When standardized for age, men actually had higher rates of both primary (586 vs. 465 per 100,000 people) and secondary (1,526 vs. 1,324 per 100,000) HF hospitalizations than women. Mortality rates from HF coded as primary (from 4.3 to 3.2%, p < 0.001 compared with 2001) and secondary diagnoses (from 8.1 to 6.2%, p < 0.001 compared with 2001) decreased with time, but mortality rates overall were higher in those with HF coded as a secondary diagnosis.


Rates of primary HF diagnoses decreased in the United States, but HF remains a common secondary diagnosis for admission.


Given the health care burden and expenses associated with HF management, HF care quality and reimbursement is the focus of intense scrutiny. In order to appreciate the battle ahead, an understanding of HF admissions rate trends needs to be ascertained. This study demonstrated that rates of primary HF admissions decreased from 2001-2009. However, the burden of HF is not really on the decline given the increased rates of HF coded as a secondary diagnosis. The authors question if changes in coding (called ‘down coding’) due to quality measure tracking by Medicare may be responsible for such trends. Time will be needed to further sort out this question. What is also very disconcerting is the consistent and clinically significant higher mortality associated with HF coded as a secondary diagnosis. This study shows that HF patients in the United States have high comorbidity burdens. It is reasonable to assume HF may drive exacerbation of comorbidities (i.e., renal failure), and other comorbidities could induce HF exacerbations. Thus, focusing quality on HF alone may just address one piece of a very complicated puzzle.

Keywords: Heart Diseases, Renal Insufficiency, Cardiology, Heart Failure, Inpatients, Patient Discharge, Hospitalization, United States, Lung Diseases

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