Long-Term Outcomes and Independent Predictors of Mortality in Patients Presenting to Emergency Departments with Acute Heart Failure in Beijing: A Multicenter Cohort Study with a 5-Year Follow-Up
Acute heart failure (AHF) is a major public health issue globally, characterized by high morbidity and mortality rates. It is the most common cause of emergency department (ED) admissions, yet clinical data exploring the long-term outcomes of patients presenting with AHF in EDs remain limited. This study aimed to describe the long-term outcomes of patients with AHF in EDs and identify the independent predictors of mortality over a 5-year follow-up period.
Study Design and Methodology
This prospective, multicenter cohort study consecutively enrolled 3,335 patients diagnosed with AHF who were admitted to the EDs of 14 hospitals in Beijing between January 1, 2011, and September 23, 2012. The diagnosis of AHF was made by attending physicians based on symptomatic lung congestion confirmed by chest X-ray or objective findings consistent with left ventricular dysfunction. The study collected comprehensive data on patient demographics, medical history, physical signs, laboratory tests, imaging results, and treatment strategies during the ED stay and follow-up period.
The primary outcomes of interest were 5-year all-cause mortality and cardiovascular (CV) deaths. CV deaths were defined as deaths resulting from acute myocardial infarction, sudden cardiac death, heart failure, stroke, CV procedures, CV hemorrhage, or other CV causes. Patients were followed up via telephone or outpatient visits, and death events were confirmed by checking death certificates obtained from the residence registration system.
Patient Characteristics
The median age of the enrolled patients was 71 years, with 46.8% being female. The mean body mass index (BMI) was 23.9 kg/m². Approximately half of the patients (50.04%) had new-onset heart failure, while the other half (49.96%) had decompensated chronic heart failure. The most common etiologies of AHF were ischemic heart disease (43.3%), hypertensive heart disease (17.3%), and primary cardiomyopathy (16.1%). Infection was the most common precipitating factor, present in 71.0% of cases.
At ED admission, the mean heart rate was 98.6 beats per minute, and the mean diastolic blood pressure (DBP) was 78.4 mmHg. The median B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were 1,280 pg/mL and 4,920 pg/mL, respectively. Left ventricular ejection fraction (LVEF) data were available for 62.5% of patients, with a median LVEF of 44%. Among these patients, 43.7% had an LVEF <40%, 15.5% had an LVEF between 40% and 49%, and 40.8% had an LVEF ≥50%. The majority of patients (87.6%) were classified as New York Heart Association (NYHA) functional class III or IV.
Five-Year Outcomes
The 5-year follow-up revealed a high mortality rate among patients with AHF. The all-cause mortality rate was 55.4%, and the CV death rate was 49.6%. The median overall survival was 34 months. Notably, 22.6% of patients died within the first month, and 39.2% died within the first year after the onset of AHF. The remaining 60.8% of deaths occurred between the second and fifth years.
Independent Predictors of 5-Year Mortality
Multivariate Cox regression analysis identified several independent predictors of 5-year all-cause mortality. Older age (hazard ratio [HR]: 1.027, 95% confidence interval [CI]: 1.023–1.030), lower BMI (HR: 0.971, 95% CI: 0.958–0.983), presence of fatigue (HR: 1.127, 95% CI: 1.009–1.258), ascites (HR: 1.190, 95% CI: 1.057–1.340), hepatic jugular reflux (HR: 1.339, 95% CI: 1.140–1.572), NYHA class III to IV (HR: 1.511, 95% CI: 1.291–1.769), higher heart rate (HR: 1.003, 95% CI: 1.001–1.005), lower DBP (HR: 0.996, 95% CI: 0.993–0.999), higher blood urea nitrogen (BUN) levels (HR: 1.014, 95% CI: 1.008–1.020), and elevated BNP/NT-proBNP levels in the third (HR: 1.426, 95% CI: 1.220–1.668) or fourth quartile (HR: 1.437, 95% CI: 1.223–1.690) were associated with increased mortality. Additionally, lower serum sodium (HR: 0.980, 95% CI: 0.972–0.988) and serum albumin levels (HR: 0.981, 95% CI: 0.971–0.992) were also significant predictors.
Patients with AHF caused by ischemic heart disease (HR: 1.195, 95% CI: 1.073–1.331) or primary cardiomyopathy (HR: 1.382, 95% CI: 1.183–1.614) had a higher risk of mortality. Comorbidities such as diabetes (HR: 1.118, 95% CI: 1.010–1.237) and stroke (HR: 1.252, 95% CI: 1.121–1.397) were also associated with increased mortality.
Conversely, the use of certain medications was associated with improved survival. These included diuretics (HR: 0.714, 95% CI: 0.626–0.814), beta-blockers (HR: 0.673, 95% CI: 0.588–0.769), angiotensin-converting enzyme inhibitors (ACEIs) (HR: 0.714, 95% CI: 0.604–0.845), angiotensin-II receptor blockers (ARBs) (HR: 0.790, 95% CI: 0.646–0.965), spironolactone (HR: 0.814, 95% CI: 0.663–0.999), calcium antagonists (HR: 0.624, 95% CI: 0.531–0.733), nitrates (HR: 0.715, 95% CI: 0.631–0.811), and digoxin (HR: 0.579, 95% CI: 0.465–0.721).
Predictors of 5-Year Cardiovascular Death
The predictors of 5-year CV death were largely similar to those of all-cause mortality. However, fatigue was no longer a significant predictor, while the presence of orthopnea, comorbid digestive system diseases, higher white blood cell counts, and lower platelet counts emerged as additional independent risk factors for CV death.
Discussion
This study provides critical insights into the long-term outcomes and prognostic factors of patients with AHF presenting to EDs. The findings highlight the poor prognosis of AHF, with a 5-year mortality rate of 55.4% and a CV death rate of 49.6%. The median overall survival of 34 months underscores the need for improved management strategies for these patients.
The identification of independent predictors of mortality offers valuable information for risk stratification and targeted interventions. Older age, lower BMI, and specific clinical signs such as ascites and hepatic jugular reflux were strongly associated with increased mortality. The presence of comorbidities such as diabetes and stroke further exacerbated the risk. Conversely, the use of guideline-recommended medications, including diuretics, beta-blockers, ACEIs, ARBs, and spironolactone, was associated with improved survival, emphasizing the importance of optimizing pharmacotherapy in AHF management.
The study also sheds light on the prognostic significance of laboratory markers such as BNP/NT-proBNP levels, serum sodium, and serum albumin. Elevated BNP/NT-proBNP levels, in particular, were strongly predictive of increased mortality, reinforcing their role as valuable biomarkers in AHF.
Interestingly, the study found that LVEF and the classification of heart failure based on LVEF were not significantly associated with mortality. This finding challenges the traditional emphasis on LVEF in risk stratification and suggests that other factors, such as clinical signs and comorbidities, may play a more critical role in determining outcomes.
Limitations
Several limitations should be acknowledged. First, the relatively high lost-to-follow-up rate (11.8%) at the fifth year may have introduced bias. However, a significant proportion of these patients were confirmed to be alive in the third year, mitigating this concern to some extent. Second, missing data for certain variables, such as LVEF, were not imputed, potentially affecting the robustness of the findings. Finally, the laboratory tests were conducted in different hospitals, which may have led to variability in the results.
Conclusion
This study demonstrates the poor long-term prognosis of patients with AHF presenting to EDs, with a 5-year mortality rate of 55.4%. The identification of independent predictors of mortality, including age, BMI, clinical signs, comorbidities, and laboratory markers, provides valuable insights for risk stratification and targeted interventions. The study also highlights the importance of optimizing pharmacotherapy in AHF management, as the use of guideline-recommended medications was associated with improved survival. These findings underscore the need for continued efforts to improve the outcomes of patients with AHF, particularly in the emergency setting.
doi.org/10.1097/CM9.0000000000001617
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