Table 2 The primary author and year of publication, and heart failure as defined in the study

Macdonald (2008) [25]; Arora (2017) [26]; Omersa (2016) [27]; Howlett (2009) [28]; Madigan (2012) [29]; Robertson (2012) [30]; Blackledge (2003) [31]; Bradford (2016) [32]; Eastwood (2014) [33]; Sheppard (2005) [34]; Chun (2012) [35]; Howlett (2009) [28]; Jenghua (2011) [36]; Lee (2004) [37]

World Health Organization’s International Classification of Diseases code-10th revision; 9th revision; Australian modification

Jimenez-Navarro (2010) [38]; Goncalves (2008) [39]; Ogah (2014) [40]; Opasich (2004) [41]

European Society of Cardiology

Howie-Esquivel (2007) [42]; Sato (2015) [43]; Ogah (2014) [40]; Ogah (2015) [44]; Sajeev (2017) [45]; Lee (2004) [37]

Confirmed by a cardiologist, using standard Framingham criteria or exacerbation of a previously documented HF; Framingham criteria (including symptoms, physical examination, chest x-ray and echocardiographic findings)

Vader (2016) [46]

The presence of more than one symptom (dyspnea, orthopnea, edema) and 1 sign (rales on auscultation, peripheral edema, ascites, or pulmonary vascular congestion on chest radiography) in DOSE-AHF or ROSE-HF or admission to the hospital with a primary diagnosis in CARRESS HF

Gevaert (2014) [47]

Preserved left ventricular fraction was defined as left ventricular ejection fraction greater than or equal to 50% and heart failure with reduced ejection fraction was defined as less than 50%

Chang (2014) [48]

New onset of HF with acute decompensation or chronic HF with acute decompensation requiring hospitalization

Alla (2007) [49]

Current or past evidence of low cardiac output or congestion edema, elevated jugular venous pressure, or rales or evidence of pulmonary congestion

Ieva (2015) [50]

Diagnostic Category - Nervous system, respiratory system, circulatory system, with HF-related events, from Agency for healthcare research and quality and centres for Medicare and medicaid services hierarchical condition category in hospital administrative database

Tarantini (2002) [51]

Hospital admission for CHF

Zsilinskza (2016) [52]

Heart Failure National Registry Emergency Module (ADHERE-EM) database

Sajeev (2017) [45]

Chronic systolic HF was defined as systolic HF for at least 6 months with an EF of less than 50% and/or patients who are on standard HF medications, which include at least two groups of medications mentioned: ACEI/ARB, diuretics or digoxin

Nieminen (2008) [53]

Diastolic dysfunction was classified by the investigator as mild, moderate or severe according to echocardiographic criteria; signs of heart failure (rales, hypotension, hypoperfusion) and signs of heart failure on chest x-ray. Acute decompensated chronic heart failure was defined as worsening of heart failure in patients with a previous diagnosis or hospitalization for heart failure or as new-onset acute heart failure for patients with no prior history of heart failure

Mullens (2008) [54]

Impaired cardiac output (cardiac index < 2.4Lmin/m²)

Schwarz (2003) [55]; Otero-Ravina (2009) [56]; Ahmed (2014) [57]

Not reported; Diagnosis of HF made by a specialist (cardiologist and/or internist)