Characteristics of included studies
| First author [ref.] | Total sample size | Country | Definition of chronic cough | Study type |
| Adams [24] | 3960 | Australia | Cough lasting >12 weeks | Prospective cohort study |
| Baiardini [8] | 166 | Italy | Cough lasting >3 weeks | Study addressing item generation of a PROM (Chronic Cough Impact Questionnaire) |
| Birring [7] | 104 | UK | Cough lasting >3 weeks | Study addressing item generation of a PROM (Leicester Cough Questionnaire) |
| Campi [25] | 1204 | Italy | Cough lasting >8 weeks | Cross-sectional study |
| Chamberlain [26] | 1120 | UK, Germany, France, Italy, Poland, Russia, Ukraine, Latvia, Lithuania, Moldova, Romania, Bulgaria, Turkey, Greece, Czech Republic, Austria, Switzerland, Spain, Portugal, Ireland, Iceland, Norway, Sweden, Belgium, Netherlands, Denmark, Cyprus, Luxembourg | Cough lasting >8 weeks | Cross-sectional study |
| Chan [27] | 55 | Australia | Cough lasting >8 weeks | Cross-sectional study |
| Cheng [28] | 176 | Canada | NR | Cross-sectional study |
| Çolak [29] | 14 740 | Denmark | Cough lasting >8 weeks | Prospective cohort study |
| Çolak [30] | 14 669 | Denmark | Cough lasting >8 weeks | Prospective cohort study |
| Cornford [31] | 30 | USA | Cough lasting >3 weeks and who consulted due to cough as the primary illness | Qualitative study |
| Crawford [32] | 41 | Germany, Spain, France, Japan, USA | Daily cough and sputum production >3 months | Study addressing item generation of a PROM (Cough and Sputum Assessment Questionnaire) |
| Decalmer [33] | 62 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Everett [34] | 373 | UK | NR | Cross-sectional study |
| Everett [35] | 47 | UK | Demonstrable abnormality of oesophageal manometry or PH monitoring or both | Cross-sectional study |
| Faruqi [36] | 86 | UK, USA, Japan, Germany | NA | Qualitative study |
| Faruqi [37] | 25 | UK | Cough lasting >6 months | Prospective cohort study |
| Ford [38] | 3883 | UK | Cough lasting >8 weeks | Cross-sectional study |
| French [39] | 80 | USA | Cough lasting >8 weeks | Prospective cohort study |
| French [40] | 39 | USA | Cough lasting >3 weeks | Prospective cohort study; study addressing item generation of a PROM (Cough-Specific Quality of Life Questionnaire) |
| Fujimura [41] | 1000 | Japan | Cough lasting >8 weeks | Qualitative study |
| Hilton [42] | 100 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Hsu [14] | 47 | UK | Cough lasting >6 months | Study addressing item generation of a PROM (Cough Symptom Score) |
| Hulme [43] | 14 | UK | Cough lasting >8 weeks | Qualitative study |
| Kang [44] | 447 | Korea | Cough lasting >8 weeks | Cross-sectional study |
| Kelsall [45] | 62 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Kelsall [46] | 70 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Koo [10] | 401 | Korea | Cough lasting >8 weeks | Study addressing item generation of a PROM (Cough Assessment Test) |
| Koskela [47] | 3697 | Finland | Cough lasting >8 weeks | Cross-sectional study |
| Koskela [48] | 3695 | Finland | Cough lasting >8 weeks | Cross-sectional study |
| Kuznair [49] | 136 | USA | Cough lasting >3 weeks | Cross-sectional study |
| Lai [50] | 1162 | China | Cough lasting >8 weeks | Cross-sectional study |
| Lan [51] | 164 | Australia | Cough lasting >8 weeks | Cross-sectional study |
| Landt [52] | 41 545 | Denmark | Cough lasting >8 weeks | Prospective cohort study |
| Lätti [53] | 3673 | Finland | Cough lasting >8 weeks | Cross-sectional study |
| Lee [54] | 49 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Lee [55] | 100 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Lee [56] | 32 | UK | Cough lasting >8 weeks | Cross-sectional study |
| Ma [57] | 200 | China | Cough lasting >8 weeks | Prospective cohort study |
| Mello [58] | 88 | USA | Cough lasting >3 weeks | Cross-sectional study |
| Morice [59] | 255 | UK | Cough lasting >8 weeks | Study addressing item generation of a PROM (Hull Airway Reflux Questionnaire) |
| Murry [60] | 16 | USA | NR | Retrospective cohort study |
| Ojoo [61] | 112 | UK | Cough lasting >8 weeks | Prospective cohort study |
| Ozge [62] | 165 | Turkey | Cough lasting >4 weeks | Cross-sectional study |
| Sato [63] | 129 | Japan | NR | Cross-sectional study |
| Shariat [64] | 360 | USA | NR | Cross-sectional study |
| Shembel [65] | 365 | USA | Cough lasting >8 weeks | Study addressing item generation of a PROM (Cough Severity Index) |
| Sinha [66] | 223 | UK | Cough lasting >8 weeks | Qualitative study |
| Smith [67] | 26 | UK | CSS daytime cough score ≥2 | Cross-sectional study |
| Song [68] | 857 | Korea | Cough lasting >12 weeks | Cross-sectional analysis of a prospective cohort study |
| Ternesten-Hasseus [69] | 121 | Sweden | Cough lasting >8 weeks | Cross-sectional study |
| Van de Kerkhove [70] | 51 | Belgium | Cough lasting >8 weeks | Prospective cohort study |
| Vazquez [71] | 1422 | USA | Cough lasting >2 years | Prospective cohort study |
| Vernon [16] | 22 | USA | Cough lasting >8 weeks | Qualitative study |
| Vernon [15] | 39 | USA | Cough lasting >8 weeks | Study addressing item generation of a PROM (Cough Severity Diary) |
| Vertigan [72] | 38 | Australia | Cough lasting >8 weeks | Study addressing item generation of a PROM (Newcastle Laryngeal Hypersensitivity Questionnaire) |
| Vertigan [73] | 171 | Australia | Cough lasting >8 weeks | Cross-sectional study |
| Vertigan [74] | 171 | Australia | Cough lasting >8 weeks | Cross-sectional study |
| Vertigan [75] | 53 | Australia | Cough lasting >8 weeks | Cross-sectional study |
| Won [76] | 478 | Korea | Cough lasting >8 weeks | Cross-sectional study |
| Xu [77] | 87 | China | Cough lasting >8 weeks | Retrospective cohort study |
| Zhan [11] | 237 | China | Cough lasting >8 weeks | Study addressing item generation of a PROM (Cough Evaluation Test) |
NR: not reported; NA: not available; CSS: Cough Symptom Score; PROM: patient-reported outcome measurement.