| Variable | COPD | Non-COPD | p-value |
| Subjects n | 212 | 1167 | |
| Age yrs | 73.4±8.8 | 69.4±17.9 | 0.49 |
| Males | 191 (90.1) | 635 (54.4) | <0.01 |
| Nursing home resident | 12 (5.7) | 118 (10.2) | 0.04 |
| ICU admission | 21 (9.9) | 125 (10.7) | 0.73 |
| Mechanical ventilation | 10 (4.7) | 61 (5.2) | 0.76 |
| Noninvasive mechanical ventilation | 16 (7.5) | 45 (3.9) | 0.02 |
| PSI | 118.3±34.1 | 108.5±36.9 | <0.01 |
| PSI classes IV+V | 159 (75.4) | 769 (65.9) | 0.01 |
| CURB-65 ≥3 | 55 (27.5) | 286 (25.7) | 0.60 |
| Comorbid conditions | |||
| Heart failure | 56 (26.4) | 267 (23.0) | 0.28 |
| Chronic liver disease | 12 (5.7) | 48 (4.1) | 0.32 |
| Malignancy | 28 (13.2) | 66 (5.7) | <0.01 |
| Renal failure | 19 (9.0) | 78 (6.7) | 0.24 |
| Neurological disease | 46 (21.7) | 318 (27.2) | 0.09 |
| Diabetes mellitus | 55 (25.9) | 234 (20.2) | 0.06 |
| Pneumonia during previous year | 71 (33.8) | 198 (17.5) | <0.01 |
| COPD severity | |||
| Mild | 13 (6.1) | ||
| Moderate | 78 (36.8) | ||
| Severe | 98 (46.2) | ||
| Very severe | 23 (10.8) | ||
| History of smoking# | 202 (95.3) | 568 (48.7) | <0.01 |
| History of alcohol¶ | 63 (34.2) | 197 (17.9) | <0.01 |
| Previous antibiotic in the last month | 76 (37.1) | 322 (28.3) | 0.01 |
| Previous ICS therapy | 137 (64.9) | 148 (12.9) | <0.01 |
| Previous oral corticoid therapy | 27 (12.9) | 49 (4.2) | <0.01 |
| Physical and laboratory data | |||
| FEV1 % pred | 47.7±16.3 | ||
| Confusion | 51 (24.2) | 326 (28.1) | 0.24 |
| Respiratory rate >30 breaths·min−1 | 89 (43.4) | 385 (34.4) | 0.01 |
| Systolic blood pressure <90 mmHg | 9 (4.3) | 61 (5.3) | 0.56 |
| Heart rate >120 beats·min−1 | 27 (12.8) | 161 (13.9) | 0.67 |
| Fever | 157 (75.1) | 960 (82.9) | 0.01 |
| Temperature >39°C | 18 (8.5) | 148 (12.8) | 0.08 |
| Pa,O2/FI,O2 <250 | 270.4±67.6 | 287.8±72.3 | <0.01 |
| CRP mg·dL−1 | 17.4±12.3 | 20.5±17.6 | <0.01 |
Data are presented as mean±sd or n (%), unless otherwise stated. p-values in bold indicate statistical significance. ICU: intensive care unit; PSI: Pneumonia Severity Index; CURB-65: confusion of new onset, urea >7 mmol·L−1, respiratory rate of ≥30 breaths·min−1, blood pressure <90 mmHg systolic or diastolic blood pressure ≤60 mmHg, and age ≥65 yrs; ICS: inhaled carticosteroid; FEV1: forced expiratory volume in 1 s; % pred: % predicted; Pa,O2: arterial oxygen tension; FI,O2: inspiratory oxygen fraction; CRP: C-reactive protein. #: includes former and current smoking habit; ¶: includes former and current alcohol habit.