Table 1– Characteristics of studies included in the meta-analysis that aimed to calculate the case fatality of a chronic obstructive pulmonary disease (COPD) exacerbation
First author [ref.]Patients nMales %Mean age yrsMean FEV1 % predPatient selectionDefinition exacerbationMean hospital length of stay daysCountry
Connors 15101651700.80 L, ∼30% predPatients (aged >18 yr) with clinical diagnosis of COPD recorded by a physicianHospitalisation in combination with breathlessness, respiratory failure or change in mental status due to COPD as main reason for admission and Pa,CO2 ≥50 mmHg9USA
Vestbo 16487556760Patients (aged >20 yr) admitted for COPD (Copenhagen City Heart Study)Hospitalisation (>24 h) with primary diagnosis ICD-8: 491–492Not reportedDenmark
Groenewegen 17171617035Patients with COPD (ATS criteria), with a FEV1 <70% and reversibility <11% who were admittedIncrease of two out of three symptoms: dyspnoea, cough, sputum severe enough to warrant hospitalisation11.7Netherlands
Gunen 18205886538Patients with COPD (ATS criteria) who were admittedHospitalisation for severe increase of symptoms (cough, purulent sputum and dyspnoea), cyanosis and oedema, confusion, lethargy, coma, use of accessory muscles for ventilation, treatment failure, acidosis, hypoxaemia and/or hypercapnia or new arrhythmias11.6Turkey
McGhan 19542699769Not reportedPatients admitted for COPDHospitalisation with primary diagnosis ICD-9: 490–492 or 496 or diagnosis related group code of COPD with a primary or secondary discharge diagnosis of COPD6.5USA
Brekke 20996497147Patients (aged >40 yr) admitted for COPDHospitalisation with primary discharge diagnosis ICD-10: J44.0, J44.1, J44.x with J13-J18.9Not reportedNorway
  • FEV1: forced expiratory volume in 1 s; % pred: % predicted; ATS: American Thoracic Society; Pa,CO2: arterial carbon dioxide tension; ICD: International Classification of Diseases.