TABLE 1

Sociodemographic, clinical and functional characteristics of participants

AllCOPD hospitalisationp-value
NoYes
Baseline
 Subjects n17711067
 Male166 (94)103 (94)63 (94)1.000
 Age years71±870±871±80.725
 Marital status married146 (83)94 (86)52 (78)0.222
 Family >2 members79 (45)52 (47)27 (40)0.436
 Primary education or higher106 (60)69 (63)37 (55)0.346
 Active workers15 (8)12 (11)3 (5)0.171
 Low socioeconomic status (level IV or V)#130 (80)82 (80)48 (80)1.000
 Current smokers57 (33)37 (34)20 (30)0.765
 BMI kg·m−229±529±528±50.054
 FFMI# kg·m−220±320±319±30.168
 Dyspnoea mMRC score 0–41 (1–2)1 (0–2)2 (1–4)<0.001
 Charlson index score 0–302 (1–3)2 (1–3)2 (1–3)0.537
 Cardiovascular disease30 (17)18 (16)12 (18)0.838
 SGRQ total score 0–10032±1826±1641±18<0.001
 FEV1 % pred52±1657±1643±14<0.001
 COPD grade
  Mild (FEV1 ≥80% pred)9 (5)9 (8)0 (0)<0.001
  Moderate (FEV1 50–80% pred)87 (49)67 (61)20 (30)
  Severe (FEV1 30–50% pred)64 (36)31 (28)33 (49)
  Very severe (FEV1 <30% pred)17 (10)3 (3)14 (21)
 RV/TLC# %58±1056±1061±9<0.001
DLCO# % pred63±2167±2057±200.004
PaO2# mmHg74±1076±970±10<0.001
 6-min walking distance# m407±96424±91379±1000.003
VO2max#,¶ % pred16±417±4.615±3.90.028
 ≥1 COPD hospitalisation in the previous 12 months29 (16)6 (6)23 (34)<0.001
 Previous COPD hospitalisations in the previous 12 months+1.4 (0.8)1.0 (0.0)1.5 (0.9)<0.001
 CRP ≥3 mg·L−1119 (67)75 (74)44 (69)0.596
 Lung density# HU−842±41−849±26−832±550.215
 Emphysema# % lung tissue <−950 HU31±1431±1530±130.681
 Bronchial wall thickness extension score# (0–3)2.0±1.41.8±1.42.1±1.30.295
Follow-up
 Duration of follow-up years2.6 (2.0–3.2)
 Participation in any pulmonary rehabilitation programme19 (11)
 COPD hospitalisation during follow-up67 (38)
 COPD hospitalisations§ n2 (1–3)
 Time to first COPD hospitalisation§ years0.7 (0.3–1.3)
 Mortality28 (16)
  • Data are presented as n, n (%), mean±sd or median (interquartile range), unless otherwise stated. COPD: chronic obstructive pulmonary disease; BMI: body mass index; FFMI: fat-free mass index; mMRC: modified Medical Research Council; SGRQ: St George's Respiratory Questionnaire; FEV1: forced expiratory volume in 1 s; RV: residual volume; TLC: total lung capacity; DLCO: diffusing capacity of the lung for carbon monoxide; % pred: % predicted; PaO2: arterial oxygen tension; VO2max: maximal oxygen uptake; CRP: C-reactive protein. #: some variables have missing values: socioeconomic status (n=15), FFMI (n=13), RV/TLC (n=11), DLCO (n=17), PaO2 (n=6), 6-min walking distance (n=10), VO2max (n=66), CRP (n=11), lung density and emphysema (n=112) and bronchial wall thickness (n=96). Missing values were distributed at random and were mainly due to the hospital logistics and patient availability, as previously published [10]. : during exercise testing using the reference values of Neder et al. [13]; +: n=29; §: n=67.