Comparison of characteristics, functional markers and biomarkers between patients in the hospitalisation+ and in the hospitalisation− groups
| Hospitalisation− (n=60) | Hospitalisation+ (n=8) | P value | |
| Age | 74 (7.6) | 71 (3.6) | 0.096 |
| Body mass index, kg/m2 | 21.9 (3.0) | 19.9 (4.7) | 0.29 |
| Sex, male | 51 (85) | 7 (87.5) | >0.99 |
| Smoking, ex/current | 46 (76.7)/14 (23.3) | 8 (100)/0 (0) | 0.19 |
| Pack-years | 55 (31.8) | 65 (24.9) | 0.32 |
| GOLD classification, A/B/C/D | 19 (31.7)/22 (37.7)/ 5 (8.3)/14 (23.3) | 0 (0)/1 (12.5)/ 1 (12.5)/6 (75.0) | 0.01 |
| COPD stage 1/2/3/4 | 14 (23.3)/34 (56.7)/ 11 (18.3)/1 (1.7) | 0 (0)/4 (50)/ 1 (12.5)/3 (37.5) | 0.0006 |
| Asthma, + | 8 (13.3) | 2 (25.0) | 0.33 |
| Cerebrovascular disease, + | 7 (11.7) | 0 (0) | 0.59 |
| Pneumonia <2 year, + | 17 (28.3) | 3 (37.5) | 0.68 |
| Acute exacerbation<2 year, + | 14 (23.3) | 5 (62.5) | 0.03 |
| Hospitalisation, + | 26 (43.3) | 8 (100) | 0.005 |
| Hospitalisation<2 year, + | 19 (31.7) | 8 (100) | 0.0003 |
| mMRC scale, grade | 1.5 (1.1) | 2.8 (1.4) | 0.036 |
| CAT, point | 12.6 (8.2) | 18.3 (8.0) | 0.091 |
| LCQ, point | 18.4 (2.7) | 18.3 (2.2) | 0.93 |
| Neutrophils, /µL | 4035 (1498) | 3552 (2014) | 0.53 |
| Eosinophils, /µL | 232 (186) | 373 (318) | 0.26 |
| Eosinophils≥300/ µL, + | 8 (13.3) | 4 (50) | 0.028 |
| Albumin, g/dL | 4.0 (0.3) | 3.8 (0.5) | 0.16 |
| Lactate dehydrogenase, IU/L | 195 (33) | 198 (52) | 0.87 |
| Haemoglobin A1c, % | 6.1 (0.8) | 5.8 (0.6) | 0.32 |
| Brain natriuretic peptide, pg/mL | 55 (84) | 136 (143) | 0.16 |
| C-reactive protein, mg/L* | 0.29 (0.42) | 0.49 (0.89) | 0.54 |
| IgE, IU/L† | 362 (630) | 360 (475) | 0.99 |
| FeNO, ppb | 24.9 (15.5) | 33.7 (22.0) | 0.31 |
| C2, the number of doubling concentration | 4.5 (2.5) | 6.6 (2.7) | 0.061 |
| C5, the number of doubling concentration | 5.5 (2.4) | 7.5 (2.3) | 0.051 |
| Ejection fraction, %* | 64 (8) | 62 (15) | 0.71 |
| Postbronchodilator FEV1, mL | 1700 (643) | 1001 (550) | 0.008 |
| Postbronchodilator FEV1 predicted, % | 67.2 (21.0) | 41.5 (19.7) | 0.007 |
| Postbronchodilator FEV1/FVC, % | 51.4 (11.5) | 39.3 (16.2) | 0.076 |
| Reversibility, % | 4.7 (8.4) | 3.9 (5.9) | 0.76 |
Global Initiative for chronic obstructive lung disease.
The number of doubling concentration was shown as follows; for example, 0.61 µM, 1.22 µM, 2.44 µM, 4.88 µM, 9.76 µM, 19.52 µM, 39.04 µM, 78.1 µM, 156.2 µM and, 312.5 µM correspond to 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 doubling concentrations, respectively. *n=66, †n=64.
C2 and C5, concentrations of inhaled capsaicin required to induce at least two (C2) and five coughs (C5); CAT, COPD assessment test; FeNO, fractional nitric oxide; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; Ig, immunoglobulin; LCQ, Leicester Cough Questionnaire; mMRC, modified Medical Research Council.