Questionnaires and hand devices
| First author [ref.] | Year | Country | Sample size | Sample population | Combination | Cut-off | Sensitivity % | Specificity % | AUC |
| Fujita [38] | 2020 | Japan | 1001 | No previous diagnosis of asthma, TB and lung cancer | Changed CDQ and COPD-6 score | Joined score ≥27 | 87.8 | 73.1 | 0.87 |
| Sichletidis[26] | 2011 | Greece | 1078 | ≥40 years of age and no previous diagnosis of COPD | CDQ and Piko-6 | Questionnaire score ≥17 and post-bronchodilator FEV1/FEV6 <0.7 | 72 | 97 | NA |
AUC: area under the curve; TB: tuberculosis; CDQ: COPD diagnostic questionnaire; FEV1: forced expiratory volume in 1 s; FEV6: forced expiratory volume in 6 s; NA: not available.