Patient characteristics by recruitment outcome
| Total | Eligible | Not eligible | Modelling eligibility OR (95% CI)# | Enrolled | Declined | Modelling enrolment OR (95% CI)¶ | |
| Participants, n | 439 | 253 | 186 | 183 | 70 | ||
| Age groups+, n (%) | |||||||
| <60 years | 45 (10) | 19 (8) | 26 (15) | 0.32 (0.15–0.71)** | 17 (9) | 2 (3) | 4.71 (0.58–38.19) |
| 60–69 years | 97 (22) | 68 (27) | 29 (17) | 1.20 (0.68–2.12) | 52 (28) | 16 (24) | 0.91 (0.43–1.90) |
| 70–79 years (ref.) | 197 (45) | 124 (50) | 73 (42) | Ref. | 90 (49) | 34 (52) | Ref. |
| >80 years | 82 (19) | 38 (15) | 44 (26) | 0.39 (0.22–0.70)** | 24 (13) | 14 (21) | 0.49 (0.21–1.15) |
| Female, n (%) | 237 (54) | 138 (55) | 99 (53) | 1.10 (0.71–1.71) | 93 (51) | 45 (64) | 0.47 (0.25–0.88)* |
| Male (ref.), n (%) | 115 (45) | 87 (47) | Ref. | 90 (49) | 25 (36) | Ref. | |
| mMRC§, n (%) | |||||||
| 1=moderate | 85 (19) | 25 (10) | 60 (33) | 0.27 (0.15–0.52)*** | 16 (9) | 9 (13) | 0.50 (0.18–1.41) |
| 2=strong (ref.) | 134 (31) | 85 (34) | 49 (27) | Ref. | 68 (37) | 17 (25) | Ref. |
| 3=very strong | 214 (49) | 142 (56) | 72 (40) | 0.90 (0.54–1.49) | 99 (54) | 43 (62) | 0.83 (0.41–1.67) |
| Recruitment routeƒ, n (%) | |||||||
| Media (ref.) | 257 (58) | 122 (50) | 135 (76) | Ref. | 81 (46) | 41 (61) | Ref. |
| Clinical | 91 (21) | 67 (27) | 24 (14) | 2.82 (1.55–5.14)*** | 47 (26) | 20 (30) | 1.07 (0.52–2.18) |
| Social | 74 (17) | 56 (23) | 18 (10) | 3.15 (1.67–5.94)*** | 50 (28) | 6 (9) | 4.76 (1.70–13.38)** |
ref.: reference; mMRC: modified Medical Research Council dyspnoea scale. #: missing in regression model: n=35; ¶: missing in regression model: n=12; +: age at first contact (missing n=18: n=4 declined, n=14 not eligible); §: 0=breathless with strenuous exercise, 1=breathless when hurrying on the level/walking up, 2=stop for breath when walking at my own pace, 3=stop for breath after ∼100 m, 4=breathless when getting dressed (missing n=6: n=1 declined, n=5 not eligible); for the regression model, mMRC categories 0 and 1 and mMRC categories 3 and 4 were merged due to low cell counts (category “0”: n=0 enrolled, n=0 declined, n=13 excluded; category “4”: n=6 enrolment, n=8 declined, n=8 not eligible); ƒ: missing: n=17 (n=5 enrolled, n=3 declined, n=9 excluded). *: p<0.05, **: p<0.01, ***: p<0.001.