Table 3– Characteristics of studies with a follow-up <1.5 yrs excluded from the meta-analysis used to obtain information on mortality rates at different time-points after a severe exacerbation as presented in the literature

First author [ref.]	Patients n	Males %	Mean age yrs	Mean FEV₁% pred	Patient selection	Definition exacerbation	Mean hospital length of stay days	Country
Fuso 10	590	79	68	Not reported	Patients with COPD (ATS criteria) who were admitted	Increased dyspnoea, reduced usual performance with or without change in sputum, blood temperature and body weight <5 days prior to hospitalisation	Not reported	Italy
Cydulka 21	131974	49	75	Not reported	Patients (aged >65 yrs) admitted for COPD	Hospitalisation with first diagnosis ICD-9: 490–492, 496	6	USA
Eriksen 22	300	40	71	35	Patients with COPD, confirmed by physician or spirometry, who were admitted	Hospitalisation for COPD exacerbation: J44.0, 44.1, 44.8, 44.9	9.9	Denmark
Patil 9	71130	44	70	Not reported	Patients (aged >40 yrs) admitted for COPD	Hospitalisation with discharge code ICD-9: 491.21	5	USA
Yohannes 23	104	48	73	40	Patients (aged >60 yrs) admitted for COPD	Hospitalisation for exacerbation defined as: presence of at least two symptoms: increased sputum purulence or volume, dyspnoea, wheeze, chest tightness or fluid retention	15	UK
Wang 24	282	41	71	36	Patients (>40 yrs), smoker/ex-smoker, FEV₁<80%, FEV₁/FVC<70% and no other lung disease who were admitted	Hospital admission for an acute exacerbation of COPD	10	Canada
Price 25	7529	Not reported	Not reported	Not reported	Patients with physician-diagnosed COPD who were admitted	Acute hospital admission for COPD	8.3	UK
Bustamente 26	763	81	76	47	Patients (aged >45 yrs) with COPD according to GOLD who were admitted	Hospitalisation with diagnosis ICD-9: 491.21	10.6	Spain
Kinnunen 27	72896^#	74	72	Not reported	Patients (aged >44 yrs) admitted for COPD	Hospital admission with primary diagnosis ICD-8,9: 491, 942, 496 ICD-10: J41, 42, 43, 44	8.1	Finland
Dransfield 28	825	50	66	Not reported	Patients admitted for COPD	Hospitalisation with primary discharge code ICD-9: 491.21 or primary diagnosis of respiratory failure 518.81 with second diagnosis COPD exacerbation	5.7	USA

FEV1: forced expiratory volume in 1 s; % pred: % predicted; COPD: chronic obstructive pulmonary disease; ATS: American Thoracic Society; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; ICD: International Classification of Diseases. ^#: number of admissions instead of number of patients.