TABLE 6.
The top 20 keywords of COPD drugs-related studies that were published from 1980 to 2021.
| Rank | Frequency | Centrality | Key words |
|---|---|---|---|
| 1 | 1,312 | 0.04 | COPD |
| 2 | 717 | 0.03 | Obstructive pulmonary disease |
| 3 | 286 | 0.02 | Exacerbation |
| 4 | 244 | 0.03 | Tiotropium |
| 5 | 206 | 0.06 | Mortality |
| 6 | 192 | 0.05 | Management |
| 7 | 176 | 0.03 | Therapy |
| 8 | 173 | 0.05 | Double blind |
| 9 | 170 | 0.12 | Efficacy |
| 10 | 169 | 0.01 | Lung function |
| 11 | 155 | 0.02 | Inflammation |
| 12 | 147 | 0.02 | Risk |
| 13 | 143 | 0.01 | Salmeterol |
| 14 | 136 | 0.01 | Safety |
| 15 | 131 | 0.11 | Disease |
| 16 | 131 | 0.05 | Prevalence |
| 17 | 115 | 0.03 | Bronchodilator |
| 18 | 105 | 0.03 | Quality of life |
| 19 | 102 | 0.04 | Chronic bronchiti |
| 20 | 101 | 0.03 | Acute exacerbation |