Heart failure
Long-Term Outcomes of Medicare Beneficiaries With Worsening Renal Function During Hospitalization for Heart Failure

https://doi.org/10.1016/j.amjcard.2010.01.361Get rights and content

We examined whether worsening renal function (RF) was associated with long-term mortality, readmission, and inpatient costs in Medicare beneficiaries hospitalized with heart failure (HF). Baseline renal insufficiency in patients hospitalized for HF is associated with increased risk of morbidity and mortality. However, the relation between worsening RF and long-term clinical outcomes is unclear. We linked clinical registry data to Medicare inpatient claims to identify 1-year outcomes of patients ≥65 years of age hospitalized with HF. Worsening RF was defined as a change in serum creatinine ≥0.3 mg/dl. Relations between worsening RF and 1-year mortality and readmission were evaluated with multivariable Cox proportional hazards models with robust SEs; associations with inpatient costs were evaluated with generalized linear models with a log-link and Poisson distribution. Of 20,063 patients hospitalized with HF and discharged alive, 3,581 (17.8%) had worsening RF during the index hospitalization. One year after discharge, 35.4% of these patients died, 64.5% were readmitted, and average costs at 1 year were $14,829 (interquartile range 0 to 19,366). After adjustment for patient characteristics, baseline RF, and comorbid conditions, worsening RF was independently associated with 1-year mortality (hazard ratio 1.12, 95% confidence interval 1.04 to 1.20) but not readmission or total inpatient costs. In conclusion, worsening RF in patients hospitalized with HF was independently associated with long-term mortality.

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Methods

We accessed clinical data for the study from the OPTIMIZE-HF registry. We also obtained research-identifiable Medicare claims data from the Centers for Medicare and Medicaid Services. The OPTIMIZE-HF registry contains data for patients admitted with HF from January 1, 2003, through December 31, 2004, at 259 participating hospitals.8, 9, 10 Eligible patients were those who presented with symptoms of HF during a hospitalization for which HF was the primary discharge diagnosis or for whom

Results

After we linked OPTIMIZE-HF hospitalizations to Medicare inpatient claims and applied the exclusion criteria, the study population included 20,063 patients hospitalized with HF, of whom 3,581 (17.8%) had worsening RF at discharge. Median age was 80 years, and 56.2% were women. Cause of HF was ischemic in 9,671 patients (48.2%), and 7,246 patients (36.1%) had systolic dysfunction.

Table 1 lists baseline demographic characteristics of patients with worsening RF and those without. Patients with

Discussion

This analysis is the first large study of patients hospitalized with acute HF outside clinical trial settings to show a significant association between worsening RF and 1-year all-cause mortality. Although we found several predictors of long-term mortality, worsening RF remained an independent predictor after adjustment for baseline characteristics and comorbid conditions. Weinfeld et al8 reported an association between worsening RF during HF hospitalization and long-term mortality; however,

Acknowledgment

We thank Damon M. Seils, MA, Duke University, for assistance with preparation of this report. Mr. Seils did not receive compensation for his assistance apart from his employment at the institution where the study was conducted.

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This study was funded by an unrestricted educational grant from Merck & Co., Whitehouse Station, New Jersey. The OPTIMIZE-HF registry was funded by GlaxoSmithKline, Research Triangle Park, North Carolina. Dr. Hernandez is supported by American Heart Association Pharmaceutical Roundtable Grant 0675060N. Dr. Fonarow is supported by the Ahmanson Foundation, Beverly Hills, California, and the Corday Family Foundation, Beverly Hills, California.

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