Descriptive statistics for characteristics at baseline visits
| Characteristic/factor# | Baseline visits (n=445)¶ | No viral infection (n=419) | Viral Infection (n=22) | p-value | |
| Age years | n | 445 | 419 | 22 | 0.048 |
| Mean±sd | 66±9 | 67±9 | 63±8 | ||
| Median (IQR) | 67 (61–74) | 67 (61–74) | 63 (58–70) | ||
| Median (range) | 67 (37–89) | 67 (37–88) | 63 (48–81) | ||
| Body mass index | n | 445 | 419 | 22 | 0.044 |
| Mean±sd | 27.2±6.3 | 27.0±6.3 | 30.2±7.1 | ||
| Median (IQR) | 26.1 (22.8–30.6) | 25.9 (22.6–30.4) | 28.8 (23.5–34.5) | ||
| Median (range) | 26.1 (14.5–62.2) | 25.9 (14.4–62.2) | 28.8 (18.9–42.6) | ||
| Malignant lymphoma | No | 443 (99.5) | 20 (90.9) | 419 (100) | 0.002 |
| Yes | 2 (0.4) | 2 (9.1) | 0 (0) | ||
| Insulin | No | 428 (96.2) | 19 (86.36) | 405 (96.6) | 0.046 |
| Yes | 17 (3.8) | 3 (13.6) | 14 (3.3) | ||
| Post-bronchodilator FEV1 L | n | 424 | 399 | 22 | 0.002 |
| Mean±sd | 1.4±0.5 | 1.4±0.5 | 1.8±0.5 | ||
| Median (IQR) | 1.4 (1.0–1.8) | 1.4 (1.0–1.8) | 1.8 (1.4–2.3) | ||
| Median (range) | 1.4 (0.3–3.1) | 1.4 (0.3–3.1) | 1.8 (0.7–2.7) | ||
| Post-bronchodilator FEV1 % pred | n | 424 | 399 | 22 | 0.002 |
| Mean±sd | 54.7±16.9 | 54.0±16.8 | 65.7±15.5 | ||
| Median (IQR) | 55.2 (42.6–67.7) | 55.0 (42.1–66.8) | 70.5 (49.9–75.0) | ||
| Median (range) | 55.2 (16.0–97.0) | 55.0 (16.0–97.0) | 70.5 (34.5–97.0) | ||
| Post-bronchodilator FEV1/VCmax | n | 424 | 399 | 22 | 0.015 |
| Mean±sd | 45.5±13.4 | 45.0±13.2 | 53.2±14.6 | ||
| Median (IQR) | 44.7 (35.7–55.9) | 44.5 (34.9–55.6) | 51.7 (40.6–62.5) | ||
| Median (range) | 44.7 (15.4–84.0) | 44.5 (15.4–78.0) | 51.7 (27.6–84.0) | ||
| Post-bronchodilator RV/TLC | n | 372 | 351 | 19 | 0.018 |
| Mean±sd | 51.4±9.7 | 51.7±9.5 | 45.0±12.0 | ||
| Median (IQR) | 51.2 (44.8–57.3) | 51.5 (45.1–58.1) | 46.1 (41.3–52.0) | ||
| Median (range) | 51.2 (2.3–79.9) | 51.5 (29.0–79.9) | 46.1 (2.3–61.9) | ||
| Post-bronchodilator DLCO SB % pred | n | 357 | 338 | 18 | 0.017 |
| Mean±sd | 55.9±19.4 | 55.2±19.3 | 66.9±18.7 | ||
| Median (IQR) | 55.4 (41.0–70.6) | 55.1 (40.0–69.7) | 62.9 (54.7–76.4) | ||
| Median (range) | 55.4 (11.8–107.6) | 55.1 (11.8–107.6) | 62.9 (31.4–99.9) | ||
| Post-bronchodilator DLCO/VA % pred | n | 354 | 335 | 18 | 0.043 |
| Mean±sd | 69.4±24.8 | 68.7±24.7 | 80.3±22.5 | ||
| Median (IQR) | 66.7 (50.5–88.4) | 66.3 (50.1–87.8) | 85.9 (63.3–101.0) | ||
| Median (range) | 66.75 (0.72–140.4) | 66.3 (0.72–140.4) | 85.9 (41.2–114.1) | ||
| BODE score | n | 370 | 347 | 21 | 0.021 |
| Mean±sd | 2.5±2.0 | 2.6±2.0 | 1.6±1.7 | ||
| Median (IQR) | 2 (1–4) | 2 (1–4) | 1 (0–2) | ||
| Median (range) | 2 (0–9) | 2 (0–9) | 1 (0–6) | ||
| Reversibility post-BD (change in FEV1 of ≥12% and ≥300 mL) | No | 395 (94.5) | 17 (77.3) | 375 (95.4) | 0.005 |
| yes | 23 (5.5) | 5 (22.7) | 18 (4.6) | ||
| Reversibility post-BD (change in FEV1 of ≥12% and ≥200 mL) | No | 390 (93.3) | 17 (77.3) | 370 (94.1) | 0.011 |
| Yes | 28 (6.7) | 5 (22.7) | 23 (5.8) |
Lung function parameters were also assessed pre-bronchodilation and values were similar to those presented for post-bronchodilation. FEV1: forced expiratory volume in 1 s; VCmax: maximum vital capacity; RV: residual volume; TLC: total lung capacity; DLCO : diffusing capacity of the lung for carbon monoxide; SB: single breath; VA: alveolar volume; BODE: body mass index, airflow obstruction, dyspnoea, and exercise; BD: bronchodilator; IQR: interquartile range. #: among the parameters that were tested (sex, smoking status, shortness of breath, cough, wheezing, sputum production, inhaled medication, systemic medication, oxygen therapy, noninvasive ventilation, surgical therapy for COPD, comorbidities, modified Medical Research Council dyspnoea scale, St George's Respiratory Questionnaire, COPD Assessment Test score, microbiology in sputum, Global Initiative for Obstructive Lung Disease (GOLD) stage and group, and lung function parameters including SB, NO in exhaled air and 6-min walking distance), only statistically significant parameters are presented. ¶: four patients had no information on viral infection.