Characterization of Risk Factors for Heart Failure
What is the comparative frequency of precipitating clinical factors leading to hospitalization among heart failure (HF) patients with reduced, borderline, and preserved ejection fraction (EF)?
The study authors analyzed the factors potentially contributing to HF hospitalization among 99,825 HF admissions from 305 hospitals in the Get With The Guidelines-HF (GWTG-HF) database between January 2005 and September 2013, and assessed their association with length of stay and in-hospital mortality. They divided the study cohort into those subjects with reduced EF (EF <40% or, if EF was missing, qualitative assessment of moderate to severe dysfunction), patients with borderline systolic function (40% ≤EF <50%), and those with preserved EF (EF ≥50% or, if EF was missing, qualitative assessment of normal or mild dysfunction). They excluded patients without a documented EF. They performed multivariate logistic regression for each factor individually using the generalized estimating equations method to adjust for clustering within hospitals to determine whether comorbid factors independently influenced each outcome.
The study authors found that mean age in the study cohort was 72.6 ± 14.2 years, 49% were female, and mean EF was 39.3 ± 17.2%. Common factors included pneumonia/respiratory process (28.2%), arrhythmia (21.7%), medication noncompliance (15.8%), worsening renal failure (14.7%), and uncontrolled hypertension (14.5%). Uncontrolled hypertension was more likely to be present in patients with borderline EF (16.4%) and pneumonia/respiratory process was more likely in patients with preserved EF (32.7%). In patients with borderline EF (EF 40-49%), pneumonia was associated with longer hospital stay, whereas dietary and medication noncompliance were associated with reduced length of stay. In patients with preserved EF (EF ≥50% or qualitative assessment of normal or mild dysfunction), pneumonia, weight gain, and worsening renal function were independently associated with longer lengths of stay. Worsening renal function and pneumonia were independently associated with higher in-hospital mortality in all HF groups, and acute pulmonary edema was associated with higher mortality in reduced EF. Dietary noncompliance (14.7%) was associated with reduced mortality for all groups more often in patients with reduced EF (16.8% and 19.7%, respectively) and reached statistical significance in the subgroups of reduced (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.46-0.91) and preserved systolic function (OR, 0.52; 95% CI, 0.33-0.83). They found that patients presenting with ischemia had a higher mortality rate (OR, 1.31; 95% CI, 1.02-1.69; and 1.72; 95% CI, 1.27-2.33, respectively, in the two groups).
The study authors concluded that potential precipitating factors among patients hospitalized with HF vary by EF group and are independently associated with clinical outcomes.
This is an important study because it emphasizes the importance of heightened awareness of modifiable risk factors for HF with the hope that patients will benefit from closer monitoring and early intervention. One such factor is dietary noncompliance, which is associated with increased mortality—optimizing patient education should improve survival.
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