Table 1. Characteristics of pneumonia by study group.
| Variable | Patients with COPD [n = 983],n (%) | Patients without COPD [n = 3138],n (%) | p value |
| Demographic data | |||
| Age, median (IQR), years | 74 (67–80) | 67 (52–78) | <0.001 |
| >65 years old | 785 (79.9) | 1730 (55.2) | <0.001 |
| Male sex | 890 (90.5) | 1912 (61) | <0.001 |
| Current smoker | 252 (25.8) | 827 (26.6) | <0.001 |
| Ex-smoker | 535 (54.8) | 744 (23.9) | |
| Alcohol abuse | 195 (20) | 491 (15.8) | 0.002 |
| Influenza vaccine (season) | 627 (71.4) | 1199 (42.6) | <0.001 |
| Pneumococcal vaccine, 5 years | 226 (26.8) | 381 (13.9) | <0.001 |
| Comorbid conditions | |||
| Diabetes mellitus | 216 (22) | 639 (20.4) | 0.280 |
| Chronic heart disease | 265 (27) | 688 (21.9) | 0.001 |
| Neoplastic disease | 112 (11.4) | 255 (8.1) | 0.003 |
| Chronic renal disease | 67 (6.8) | 219 (7) | 0.943 |
| Chronic liver disease | 63 (6.4) | 200 (6.4) | 1 |
| Cerebrovascular disease | 69 (7) | 243 (7.7) | 0.490 |
| Cognitive deficit (dementia) | 38 (3.9) | 174 (5.5) | 0.038 |
| Statin use1 | 89 (25.8) | 220 (20.9) | 0.062 |
| Chronic oral steroids | 102 (10.4) | 159 (5.1) | <0.001 |
| Pre-hospital antibiotics | 191 (19.1) | 729 (23.9) | 0.002 |
| Prior antibiotic treatment | 227 (23.1) | 443 (14.1) | <0.001 |
| Prior hospitalization (90 days)2 | 91 (12.3) | 129 (5.5) | <0.001 |
| Criteria of health-care associated pneumonia3 | 194 (26.2) | 461 (19.7) | <0.001 |
| Clinical features at presentation | |||
| Fever (≥38.0°C) | 437 (45) | 1645 (52.9) | <0.001 |
| Acute onset of disease | 446 (45.5) | 1385 (44.3) | 0.532 |
| Days of clinical symptoms at admission (IQR) | 3 (1–5) | 4 (2–6) | <0.001 |
| Cough | 859 (87.6) | 2592 (83.2) | 0.001 |
| Expectoration | 734 (74.8) | 1812 (58) | <0.001 |
| Purulent sputum | 550 (63.7) | 1354 (54.9) | <0.001 |
| Dyspnea | 765 (78) | 1794 (57.4) | <0.001 |
| Tachypnea (≥30 breaths·min−1) | 429 (48.5) | 1229 (43.3) | 0.006 |
| Pleuritic chest pain | 419 (42.7) | 1276 (40.9) | 0.334 |
| Impaired consciousness | 135 (13.8) | 466 (14.9) | 0.407 |
| Septic shock | 67 (6.8) | 238 (7.6) | 0.443 |
| Diarrhea, vomiting | 85 (8.7) | 519 (16.6) | <0.001 |
| Headache | 96 (9.8) | 575 (18.4) | <0.001 |
| Arthromyalgias | 139 (14.2) | 693 (22.2) | <0.001 |
| Laboratory and radiographic findings at presentation | |||
| Respiratory failure (PaO2/FiO2<300 or PaO2<60 mmHg) | 624 (76.2) | 1563 (66.1) | <0.001 |
| Multilobar pneumonia | 255 (26) | 1095 (75.3) | <0.001 |
| Pleural effusion | 134 (13.7) | 558 (17.9) | 0.002 |
| Empyema | 21 (2.1) | 150 (4.8) | <0.001 |
| Bacteremia | 86 (9.1) | 407 (13.3) | 0.001 |
| High-risk PSI classes4 | 720 (73.5) | 1691 (54.1) | <0.001 |
COPD, chronic obstructive pulmonary disease; IQR, interquartile range; PSI, pneumonia severity index.
1
Data available only for 1396 patients. 2Data available from January 2001, only for 3084 patients; 3Data available from January 2001, only for 3084 patients 4Patients were stratified into the following risk classes according to the PSI score: low risk (≤90 points, classes I, II, and III) and high risk (>90 points, classes IV and V).