Archives of Academic Emergency Medicine. 2021; 9(1): e58 OR I G I N A L RE S E A RC H Predictive Factors of 30-day Adverse Events in Acute Heart Failure after Discharge from Emergency Department; a Historical Cohort Study Siriwimon Tantarattanapong1∗, Keerati Keeratipongpun1 1. Department of Emergency Medicine, Songklanagarind Hospital, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. Received: June 2021; Accepted: July 2021; Published online: 1 September 2021 Abstract: Introduction: The rates of unscheduled emergency department (ED) visits and readmissions after discharge from the ED in acute heart failure (AHF) patients are high. This study aimed to identify the predictive factors of 30-day adverse events after discharge from the ED. Methods: A retrospective study was conducted from 2017 to 2019 in patients diagnosed with AHF and discharged from the ED at a tertiary university hospital. Thirty-day adverse events were defined as (i) unscheduled revisit to the ED with AHF, (ii) hospital admission from AHF, and, (iii) death after discharge from the ED. The predictive factors of 30-day adverse events were examined using multivariate analyses by logistic regression. Results: 421 patients with the median age of 73 (IQR: 63-81) years were studied (52.3% male). 81 (19.2%) patients had 30-day adverse events. Significant predictive factors of 30-day adverse events consisted of underlying valvular heart disease (OR = 2.46; 95%CI: 1.27-4.78; p = 0.008), chronic obstructive pulmonary disease (COPD) (OR = 0.08; 95%CI: 0.01-0.64; p=0.001), malignancy (OR=3.63; 95%CI: 1.17-11.24; p = 0.031), New York Heart Association functional class III (OR = 4.88; 95%CI: 0.93-25.59) and IV (OR = 7.23; 95% CI: 1.37-38.08) at the ED (p = 0.035), and serum sodium <135 mmol/L (OR = 2.20; 95%CI: 1.17- 4.14; p = 0.014). Precipitating factors were anemia (OR = 2.42; 95%CI: 1.16-5.02; p = 0.021), progressive valvular heart disease (OR = 3.52; 95%CI: 1.35-7.85; p = 0.009), acute kidney injury (OR = 6.98; 95%CI: 2.32-20.96; p < 0.001), time to diuretic administration >60 minutes after ED arrival (OR = 3.89; 95%CI: 2.16-7.00; p < 0.001), and no discharge advice for follow-up (OR = 2.30; 95%CI: 1.10-4.77; p = 0.028). Conclusion: AHF patients who had good response to intravenous diuretics and were discharged from the ED were at high risk for 30-day adverse events. Ten factors predicted 30-day adverse events after discharge from the ED. Keywords: Heart failure; Patient discharge; Emergency service; hospital; Patient readmission; Patient admission Cite this article as: Tantarattanapong S, Keeratipongpun K. Predictive Factors of 30-day Adverse Events in Acute Heart Failure after Discharge from Emergency Department; a Historical Cohort Study. Arch Acad Emerg Med. 2021; 9(1): e58. https://doi.org/10.22037/aaem.v9i1.1271. 1. Introduction Acute heart failure (AHF) is defined as a rapid onset of clini- cal syndromes of heart failure such as dyspnea, fatigue, pul- monary congestion, and peripheral edema, which can be new onset (de novo) or due to the worsening of preexisting heart failure (1). The incidence of AHF is approximately 1 million cases per year in the United States of America (2). The patients present to emergency departments (EDs) and emer- ∗Corresponding Author: Siriwimon Tantarattanapong; Department of Emer- gency Medicine, Songklanagarind Hospital, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand. Phone: (66)74- 451705, Fax: (66)74-451704, Email: tsiriwimon.er@gmail.com, ORCIDs: https://orcid.org/0000-0002-4792-373X. gency physicians (EP) evaluate, diagnose, and treat AHF pa- tients. The decision making for disposition is crucial and a challenging issue for the EP. If the EP makes a decision that results in an inappropriate disposition, the risks of morbid- ity and mortality will increase (3, 4). About 16% to 36% of AHF patients can be discharged from the ED after a brief pe- riod of observation (3-6). The rate of unscheduled ED visits was reported to be 26% and readmission rate was 15% in 30 days (4). The 7-day and 30-day mortality rates in AHF pa- tients after discharge from the ED were reported to be 2% and 3.3%, respectively (3, 5). From a previous study, the factors that influenced an unscheduled ED visit and readmission of AHF patients after discharge from the ED included un- derlying ischemic heart disease, pulmonary disease, valvu- lar heart disease, anemia, malignancy, glomerular filtration This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S. Tantarattanapong and K. Keeratipongpun 2 rate (GFR) <60 mL/min/1.73 m2, and no administration of an intravenous diuretic agent (4-6). The factors that pre- dicted AHF mortality were underlying ischemic heart dis- ease, pulmonary disease, valvular heart disease, malignancy, and elevated potassium and troponin-T levels, whereas con- sumption of angiotensin-converting enzyme inhibitor, an- giotensin II receptor blocker, beta-blocker, and spironolac- tone were associated with lower mortality rates (4-6). Consideration for discharge from the ED depends on the clinical condition, good response to initial therapy, and no de novo AHF (7). However, the risk factors that influence an unscheduled ED visit, readmission, or mortality are not considered in the discharge criteria. The aim of this study was to identify the predictive factors of 30-day adverse events in AHF patients after discharge from the ED to help the EPs make appropriate dispositions. 2. Methods 2.1. Study design and setting A retrospective cohort study was conducted at the ED of Songklanagarind Hospital, which is a tertiary university hos- pital in southern Thailand. The data were collected from February 2017 to June 2019. Ethics approval was obtained from the Institutional Ethics Committee Board of the Fac- ulty of Medicine at Prince of Songkla University (Ethics code: REC.62-167-20-4). 2.2. Participants The inclusion criteria were patients aged ≥15 years, diag- nosed with AHF, and discharged home from the ED based on the decision of the EP and internists. Patients admitted or referred to other hospitals were not included in this study. The exclusion criteria were (i) end-stage renal disease with hemodialysis or peritoneal dialysis, (ii) pregnancy, (iii) in- complete discharge criteria, and (iv) lost to follow-up. 2.3. Procedure When the patients presented to the ED, the EP evaluated the history, performed physical examination, and carried out investigations to diagnose AHF according to the Framing- ham criteria and echocardiography. The Framingham crite- ria consist of (i) acute pulmonary edema, (ii) cardiomegaly, (iii) hepatojugular reflex, (iv) neck vein distension, (v) parox- ysmal nocturnal dyspnea or orthopnea, (vi) rales, and (vii) third heart sound gallop. The minor criteria consist of (i) ankle edema, (ii) dyspnea on exertion, (iii) hepatomegaly, (iv) nocturnal cough, (v) pleural effusion, and (vi) tachycar- dia (>120 beats/minute). AHF was diagnosed when two ma- jor criteria or one major and two minor criteria were met (8). After the patients were diagnosed, the EP looked for and worked up the precipitating causes and management of AHF using intravenous diuretics. The response was observed to fulfill the discharge criteria. Criteria for discharge consisted of (i) patient-reported subjective improvement, (ii) resting heart rate <100 bpm, (iii) no hypotension, (iv) adequate urine output, (v) oxygen saturation >95% in room air, and (vi) no de novo heart failure (7). Adequate urine output was defined as urine output >100 mL/h after intravenous diuretic adminis- tration (9). 2.4. Data gathering The data collected from the medical records included pa- tient baseline characteristics, history taking, physical exami- nation, precipitating factors, diagnosis, investigations, treat- ments, and 30-day adverse events. Thirty-day adverse events were defined as (i) unscheduled revisit to the ED with AHF within 30 days, (ii) hospital admission due to AHF within 30 days after discharge from the ED, and (iii) death within 30 days after discharge from the ED. Time to diuretic administration was considered as the inter- val from the time the patient entered the ED until the patient received the first dose of an intravenous diuretic agent. 2.5. Outcome measurements The primary outcome was to identify the predictive factors of 30-day adverse events in AHF patients who were discharged home from the ED. The secondary outcome was to identify the incidence of 30-day adverse events. 2.6. Statistical Analysis The sample size was calculated using the n4Studies based on a study by Miró et al. (4). The statistical analysis was con- ducted using R software version 3.6.1. Continuous variables were analyzed and are reported as median and interquartile range (IQR), while discrete variables are reported as percent- age. All data were based on non-parametric frequency distri- butions. The univariate model analyzed the baseline char- acteristics, clinical presentations, investigations, and treat- ments. The data were compared between subjects with and without 30-day adverse events after discharge from the ED. Continuous variables were compared using the Mann- Whitney U-test. Categorical variables were compared us- ing the X2 test or Fisher’s exact test as indicated. Significant predictive factors associated with 30-day adverse events in AHF (p < 0.2) identified during the univariate analysis were introduced into a logistic regression model with backward stepwise selection. First-order interaction terms with com- binations of all independent predictors were introduced into the multivariate model one at a time. Generally, interaction terms were considered with statistical significance set at p < 0.05 and no significant interaction between the included variables in the final logistic regression models. Modeling re- sults are shown as odds ratio (OR) with 95% confidence in- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2021; 9(1): e58 Table 1: Comparing the baseline characteristics between acute heart failure patients with and without 30-day adverse outcome Variables 30-day adverse event p value With (n=81) Without (n=340) Age (year) Median (IQR) 73 (62,79) 73 (62,81) 0.305 Sex Male 36 (44.4) 184 (54.1) 0.149 Female 45 (55.6) 156 (45.9) Baseline NYHA functional class I 3 (3.7) 37 (10.9) II 35 (43.2) 132 (38.8) III 26 (32.1) 89 (26.2) 0.227 IV 2 (2.5) 17 (5.0) No record 15 (18.5) 65 (19.1) Comorbidity Hypertension 49 (60.5) 230 (67.6) 0.274 Diabetes mellitus 32 (39.5) 119 (35.0) 0.528 Hyperlipidemia 34 (42.0) 138 (40.6) 0.918 Ischemic heart disease 46 (56.8) 184 (54.1) 0.757 Valvular heart disease 41 (50.6) 93 (27.4) <0.001 Atrial fibrillation 20 (24.7) 71 (20.9) 0.550 Chronic kidney disease 29 (35.8) 90 (26.5) 0.124 Cerebrovascular disease 12 (14.8) 37 (10.9) 0.424 COPD 1 (1.2) 24 (7.1) 0.063 Malignancy 9 (11.1) 14 (4.1) 0.025 Peripheral arterial disease 2 (2.5) 9 (2.6) 1.000 Medication used Diuretics 70 (86.4) 272 (80.0) 0.241 ACEI 11 (13.6) 82 (24.1) 0.057 ARB 5 (6.2) 49 (14.4) 0.071 Beta-blocker 47 (58.0) 213 (62.6) 0.521 Nitrate 20 (24.7) 66 (19.4) 0.365 Digoxin 10 (12.3) 32 (9.4) 0.558 Data are presented as n (%) or median and interquartile range (IQR). NYHA: New York Heart Association; COPD: chronic obstructive pulmonary disease; ACEI: angiotensin-converting enzyme inhibitors; ARB: angiotensin receptor blockers. terval (CI). A two-tailed p < 0.05 was selected as the level of statistical significance. 3. Results 3.1. Baseline characteristics From a total of 614 AHF patients, 421 met the inclusion cri- teria of this study. The median age was 73 (IQR 63-81) years (52.3% male). The percentages of patients with underlying valvular heart disease (50.6% vs. 27.4%; p < 0.001) and ma- lignancy (11.1% vs. 4.1%; p = 0.025) were significantly higher in the 30-day adverse event group. None of the medications used by the patients were statistically different between the two groups (Table 1). In patients with adverse events, both median systolic and di- astolic blood pressures were lower than the no adverse event group (Table 2). The mean serum sodium level in the 30- day adverse event group was also lower. The statistically significant precipitating factors that led to 30-day adverse events were anemia, non-compliance with dietary restric- tions, acute kidney injury, and progressive valvular heart dis- ease. The median times to diuretic administration in the no 30-day adverse event group and 30-day adverse event group were 53 minutes and 70 minutes, respectively (p = 0.040). The me- dian total doses of diuretic agents were higher in the 30-day adverse event group (Table 3). 3.2. Outcomes The incidence rate of 30-day adverse events after discharge from the ED was 19.2% (81/421). The rates of unscheduled revisit, hospital admission, and mortality within 30 days af- ter discharge from the ED were 17.1%, 7.6%, and 1.0%, re- spectively (Figure 1). Based on multivariate analysis, the factors that increased the odds of 30-day adverse events in- cluded underlying valvular heart disease, malignancy, New This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S. Tantarattanapong and K. Keeratipongpun 4 Table 2: Comparing the clinical presentations and laboratory findings between acute heart failure patients with and without 30-day adverse outcome Variables 30-day adverse event p value With (n=81) Without (n=340) NYHA functional class at the ED I 0 (0) 0 (0) II 2 (2.5) 31 (9.1) III 29 (35.8) 138 (40.6) 0.050 IV 36 (44.4) 105 (30.9) No record 14 (17.3) 66 (19.4) Initial vital signs SBP (mmHg) 123.0 (110.0,143.0) 138.0(120.0,154.2) <0.001 DBP (mmHg) 70.0 (61.0,79.0) 76.5 (65.0,87.0) 0.001 PR (bpm) 80.0 (70.0,96.0) 82.0 (70.0,96.0) 0.967 RR (breaths/minute) 28.0 (24.0,32.0) 28.0 (24.0,32.0) 0.499 SpO2 (%) 97.0 (95.0,99.0) 97.0 (95.0,99.0) 0.648 Laboratory findings GFR (mL/min/1.73 m2 ) 48.5 (32.0,67.0) 57.5 (37.2,75.8) 0.097 Sodium (mmol/L) 136.1 (133.0,140.8) 138.9 (135.6,141.5) <0.001 Potassium (mmol/L) 3.9 (3.5,4.3) 4.0 (3.6,4.3) 0.447 Troponin-T (ng/mL) 44.8 (29.8,70.3) 34.6 (19.4,62.4) 0.032 Pro-BNP (pg/mL) 8,041.0 (3,349.0-18,394.0) 4,805.0 (2,181.5-9,590.0) 0.110 Precipitating factors Infection 14 (17.3) 46 (13.5) 0.489 Non-STEACS 5 (6.2) 10 (2.9) 0.179 Anemia 20 (24.7) 48 (14.1) 0.031 Poor drug compliance 16 (19.8) 92 (27.1) 0.226 Non-compliance with DR 16 (19.8) 115 (33.8) 0.020 Arrhythmia 3 (3.7) 15 (4.4) 1.000 Hypertension 4 (4.9) 26 (7.6) 0.541 Acute kidney injury 10 (12.3) 11 (3.2) 0.002 Progressive VHD 19 (23.5) 24 (7.1) <0.001 Data are presented as number (%) or median and interquartile range (IQR). NYHA: New York Heart Association; ED: emergency department; SBP: systolic blood pressure; DBP: diastolic blood pressure; PR: pulse rate; RR: respiratory rate; SpO2: oxygen saturation; DR: dietary restrictions; VHD: valvular heart disease; GFR: glomerular filtration rate; Pro-BNP: N-terminal pro B-type natriuretic peptide; Non-STEACS: Non-ST elevation acute coronary syndromes. York Heart Association (NYHA) functional class III and IV at the ED, and sodium level <135 mmol/L. The precipitat- ing factors were anemia, progressive valvular heart disease, acute kidney injury, door-to-diuretic time >60 minutes, and no advice for follow-up (Table 4). However, COPD was a pre- dictive factor that decreased 30-day adverse events. 4. Discussion The overall incidence of adverse events in AHF patients dis- charged from the ED was 19.2%, which consisted of unsched- uled revisits at the ED within 30 days (17.1%), hospital admis- sion within 30 days (7.6%), and death within 30 days (1.0%). The incidences of admission to the hospital within 30 days and death within 30 days were close to previous studies at 15.7% and 1.7-4.0%, respectively (4, 5). This study revealed the predictive factors associated with 30- day adverse events after discharge from the ED, which in- cluded underlying valvular heart disease, malignancy, COPD, NYHA functional class III and IV at the ED, and serum sodium level. In addition, the precipitating factors were iden- tified to be anemia, progressive valvular heart disease, acute kidney injury, time to diuretic administration, and no advice for follow-up. The predictive factors that increased 30-day adverse events after discharge home from the ED in this study consisted of underlying valvular heart disease (adjusted OR [adj. OR] = 2.46; 95%CI: 1.27-4.78) (p = 0.008), malignancy (adj. OR = 3.63; 95%CI: 1.17-11.24) (p = 0.031), and NYHA functional class III and IV at the ED (adj. OR = 4.88; 95%CI: 0.93-25.59 and adj. OR = 7.23; 95%CI: 1.37-38.08, respectively) (p = 0.035), which were quite similar to previous studies (4, 6). In this study, COPD was a predictive factor that decreased 30- day adverse events (adj. OR = 0.08; 95%CI: 0.01-0.64) (p = This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 5 Archives of Academic Emergency Medicine. 2021; 9(1): e58 Table 3: Comparing the emergency department management and disposition characteristics between acute heart failure patients with and without 30-day adverse outcome Variables 30-day adverse event p value With (n=81) Without (n=340) Medication Time to diuretic (minutes) 70.0 (40.0,100.0) 53 (36.0,90.0) 0.040 Initial dose of IV diuretics (mg) 40.0 (40.0,80.0) 40.0 (40.0,80.0) 0.170 Total dose of IV diuretics (mg) 120.0 (40.0,240.0) 80.0 (40.0,130.0) 0.010 Consult with internist Yes 23 (28.4) 75 (22.1) 0.286 Discharge instruction items Lifestyle modification 22 (27.2) 88 (25.9) 0.925 Drug compliance 17 (21.0) 54 (15.9) 0.348 Warning signs and symptoms 40 (49.4) 134 (39.4) 0.130 Advice for follow-up 61 (75.3) 295 (86.8) 0.017 ED length of stay (hours) Median (IQR) 4.9 (3.5,6.1) 4.5 (3.3,5.6) 0.166 Data are presented as number (%) or median and interquartile range (IQR). IV: intravenous; ED: emergency department. Table 4: Predictive factors of 30-day adverse events of patients with acute heart failure who were discharged from the emergency department based on the results of multivariate logistic regression analysis Variables Crude OR Adjusted OR p value Comorbidity Valvular heart disease 2.72 (1.66-4.47) 2.46 (1.27-4.78) 0.008 COPD 0.16 (0.02-1.23) 0.08 (0.01-0.64) 0.001 Malignancy 2.91 (1.21-6.99) 3.63 (1.17-11.24) 0.031 NYHA functional class at ED III 3.26 (0.74-14.38) 4.88 (0.93-25.59) 0.035 IV 5.31 (1.21-23.33) 7.23 (1.37-38.08) Precipitating factors Anemia 1.99 (1.11-3.60) 2.42 (1.16-5.02) 0.021 Progressive valvular heart disease 4.03 (2.08-7.81) 3.52 (1.35-7.85) 0.009 Acute kidney injury 4.21 (1.72-10.3) 6.98 (2.32-20.96) <0.001 Door-to-diuretic time >60 min 2.67 (1.62-4.4) 3.89 (2.16-7.00) <0.001 Sodium <135 mmol/L 2.07 (1.22-3.53) 2.20 (1.17-4.14) 0.014 No advice for follow-up 2.15 (1.19-3.89) 2.30 (1.10-4.77) 0.028 Data are presented with 95% confidence interval; OR: odds ratio; COPD: chronic obstructive pulmonary disease; NYHA: New York Heart Association; ED: emergency department. 0.001), which was contrary to other studies (3, 4). This incon- sistency may have resulted due to different prevalence rates of COPD between the studies. The prevalence of COPD in this study was 5.9%, whereas the prevalence rates of COPD in two previous studies were 21.8% and 25.5% (3, 4). The lower prevalence of COPD in this study was possibly due to different inclusion criteria. This study included only AHF pa- tients who were discharged directly from the ED, whereas the cited studies included AHF patients discharged from the ED and AHF patients admitted to the hospital. Patients admit- ted to the hospital generally have an underlying disease such as COPD. Therefore, this study reported fewer patients with COPD. Lower serum sodium level was an associated factor for in- creased mortality in AHF patients (10). A serum sodium level <135 mmol/L was a predictive factor of adverse events in this study (adj. OR = 2.20; 95%CI: 1.17-4.14) (p = 0.014). The time to diuretic administration influenced hospital mor- tality rate. A study by Matsue et al. and Maisel reported that ED arrivals who received an intravenous diuretic agent within 60 minutes in AHF patients had a lower hospital mor- tality rate (11, 12). The results of this study showed that a door-to-diuretic time >60 minutes predicted 30-day adverse events (adj. OR = 3.89; 95%CI: 2.16-7.00) (p < 0.001). There- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S. Tantarattanapong and K. Keeratipongpun 6 Figure 1: Study inclusion flow diagram. ED: emergency department. fore, the EP should give early administration of intravenous diuretic agents within 60 minutes in AHF patients to decrease the occurrence of adverse events. Significant precipitating factors to predict 30-day adverse events in this study were anemia (adj. OR = 2.42; 95%CI: 1.16- 5.02) (p = 0.021), progressive valvular heart disease (adj. OR = 3.52; 95%CI: 1.35-7.85) (p = 0.009), and acute kidney injury (adj. OR = 6.98; 95%CI: 2.32-20.96) (p < 0.001). The EP should consider these factors in addition to the response to initial treatment prior to discharge. In accordance with the 2015 recommendations of European Society of Cardiology, the EP should identify low-risk features, absence of any known high- risk features, and a good response to the initial treatment for a safe discharge (7). Examples of high-risk features are sig- nificantly elevated natriuretic peptide levels, low blood pres- sure, worsening renal failure, hyponatremia, and positive tro- ponin. In AHF patients who have a good response to initial therapy and are considered for discharge home, the EP must give dis- charge instructions to present for follow-up within 72 hours (7). A study by VanSuch demonstrated that when all dis- charge instructions were not given, the AHF patients had an increased risk for readmission (13). In this study, no advice for follow-up was a predictive factor of 30-day adverse events This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 7 Archives of Academic Emergency Medicine. 2021; 9(1): e58 (adj. OR = 2.30; 95%CI: 1.10-4.77) (p = 0.028). Ideally the patients should present for follow-up within 72 hours after discharge, but this depends on the hospital context. The pa- tients should follow the instructions and return to the ED. The EP should make the decision for a safe discharge based on good response to initial treatment, low-risk features, and an organized system for follow-up. However, low-risk and high-risk features to predict 30-day adverse events should be researched further in the future. 5. Limitations This study was a single-center retrospective study. Therefore, missing data on the follow-up of patients affected the mortal- ity rate due to the unknown status of some patients. 6. Conclusion It seems that AHF patients who have good response to intra- venous diuretics and are discharged from the ED are at high risk for 30-day adverse events. The significant factors to pre- dict an increased risk of 30-day adverse events after discharge from the ED consisted of underlying valvular heart disease, malignancy, NYHA functional class III and IV at the ED, and serum sodium level <135 mmol/L. The precipitating factors were anemia, progressive valvular heart disease, acute kid- ney injury, time to diuretic administration >60 minutes after ED arrival, and no advice for follow-up as part of discharge instructions. On the other hand, COPD was a low risk factor of 30-day adverse events in this study. 7. Declarations 7.1. Acknowledgments The authors thank Kingkarn Waiyanak for search and re- trieval of articles, Glenn K. Shingledecker for his help in edit- ing the manuscript, and the Faculty of Medicine for funding this research. 7.2. Funding and supports The Faculty of Medicine, Prince of Songkla University funded this research. 7.3. Author contribution Keerati Keeratipongpun and Siriwimon Tantarattanapong performed the literature research, study design, data col- lection, data analysis, data interpretation, and writing the manuscript. Both authors contributed to data analysis, draft- ing, and the critical revisions of the paper and agree to be ac- countable for all aspects of the work. 7.4. Conflict of interest The authors declare they have no conflict of interest. References 1. Ponikowski P, Voors AA, Anker SD, Bueno H, Cleland JGF, Coats AJS, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardi- ology (ESC)Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. European heart journal. 2016;37(27):2129-200. 2. Collins S, Storrow AB, Albert NM, Butler J, Ezekowitz J, Felker GM, et al. Early management of patients with acute heart failure: state of the art and future directions. A consensus document from the society for academic emergency medicine/heart failure society of America acute heart failure working group. Journal of cardiac fail- ure. 2015;21(1):27-43. 3. Lee DS, Stitt A, Austin PC, Stukel TA, Schull MJ, Chong A, et al. Prediction of heart failure mortality in emer- gent care: a cohort study. Annals of internal medicine. 2012;156(11):767-75. 4. Miro O, Gil V, Martin-Sanchez FJ, Herrero P, Jacob J, Sanchez C, et al. Short-term reconsultation, hospitalisa- tion, and death rates after discharge from the emergency department in patients with acute heart failure and anal- ysis of the associated factors. The ALTUR-ICA Study. Medicina Clínica (English Edition). 2018;150(5):167-77. 5. Ezekowitz JA, Bakal JA, Kaul P, Westerhout CM, Arm- strong PW. Acute heart failure in the emergency de- partment: Short and long-term outcomes of elderly pa- tients with heart failure. European journal of heart fail- ure. 2008;10(3):308-14. 6. Lee DS, Schull MJ, Alter DA, Austin PC, Laupacis A, Chong A, et al. Early deaths in patients with heart failure discharged from the emergency department: a population-based analysis. Circulation: Heart Failure. 2010;3(2):228-35. 7. Mebazaa A, Yilmaz MB, Levy P, Ponikowski P, Peacock WF, Laribi S, et al. Recommendations on pre-hospital and early hospital management of acute heart failure: a con- sensus paper from the Heart Failure Association of the European Society of Cardiology, the European Society of Emergency Medicine and the Society of Academic Emer- gency Medicine–short version. European heart journal. 2015;36(30):1958-66. 8. King M, Kingery JE, Casey B. Diagnosis and eval- uation of heart failure. American family physician. 2012;85(12):1161-8. 9. Mullens W, Damman K, Harjola VP, Mebazaa A, Brunner- La Rocca HP, Martens P, et al. The use of diuretics in heart failure with congestion—a position statement from the Heart Failure Association of the European So- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S. Tantarattanapong and K. Keeratipongpun 8 ciety of Cardiology. European journal of heart failure. 2019;21(2):137-55. 10. Abebe TB, Gebreyohannes EA, Tefera YG, Bhagavathula AS, Erku DA, Belachew SA, et al. The prognosis of heart failure patients: Does sodium level play a significant role? PLoS One. 2018;13(11):e0207242. 11. Matsue Y, Damman K, Voors AA, Kagiyama N, Yam- aguchi T, Kuroda S, et al. Time-to-furosemide treatment and mortality in patients hospitalized with acute heart failure. Journal of the American College of Cardiology. 2017;69(25):3042-51. 12. Maisel AS, Peacock WF, McMullin N, Jessie R, Fonarow GC, Wynne J, et al. Timing of immunoreactive B-type natriuretic peptide levels and treatment delay in acute decompensated heart failure: an ADHERE (Acute De- compensated Heart Failure National Registry) analy- sis. Journal of the American College of Cardiology. 2008;52(7):534-40. 13. VanSuch M, Naessens JM, Stroebel RJ, Huddleston JM, Williams AR. Effect of discharge instructions on readmis- sion of hospitalised patients with heart failure: do all of the Joint Commission on Accreditation of Healthcare Organizations heart failure core measures reflect better care? BMJ Quality & Safety. 2006;15(6):414-7. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Methods Results Discussion Limitations Conclusion Declarations References