Table 1

Characteristics of the study participants (n=342) at their first chronic obstructive pulmonary disease (COPD) admission and during clinical stability*

At first admissionDuring clinical stability at least 3 months after the admission
Gender: female, n (%)24 (7.0)
Age (years), mean (SD)67.5 (8.5)67.9 (8.6)
Low (IV, V) socioeconomic status, n (%)259 (81.7)
Active workers, n (%)61 (17.8)54 (15.8)
Smoking status: current smoker, n (%)145 (42.4)109 (32.9)
Charlson index of co-morbidity (score 0–30), median (P25–P75)2 (1–2)2 (1–3)
Modified Medical Research Council dyspnoea scale (score 0–5), median (P25–P75)3 (2–4)2 (2–3)
Postbronchodilator forced expiratory volume in 1 s (% predicted), mean (SD)49.2 (15.7)52.4 (16.2)
Arterial oxygen partial pressure (mm Hg), mean (SD)64.8 (12.0)74.3 (10.6)
Any respiratory drug treatment, n (%)193 (56.4)288 (85.2)
  • * Subjects were recruited during their first hospital admission because of a COPD exacerbation. The assessment of phenotype heterogeneity (through the several tests and questionnaires) was done when the patient had reached clinical stability and at least 3 months after discharge (see text for more details).

  • Measured at hospital discharge.