Table 2. Differences in follow-up measures by screening eligibility and information version (n and column %).
|
Differences by screening
eligibility |
Differences by information
version |
|||||||
|---|---|---|---|---|---|---|---|---|
| Whole sample (n=2272) | Not yet eligible (n=1318) | Screening eligible (n=954) | Difference | Version 1 (3 : 1 ratio) (n=758) | Version 2 (total numbers) (n=736) | Version 3 (per 200 women) (n=778) | Difference | |
|
Breast screening intention
(post-info) | ||||||||
| Probably/definitely yes | 2041 (90.2) | 1169 (89.0) | 872 (92.0) | χ2(2)=28.8, | 683 (90.5) | 669 (91.4) | 689 (88.9) | χ2(4)=3.7, |
| Not sure | 118 (5.2) | 95 (7.2) | 23 (2.4) | P<0.0001 | 37 (4.9) | 37 (5.1) | 44 (5.7) | P=0.45 |
| Probably/definitely not | 103 (4.6) | 50 (3.8) | 53 (5.6) | 35 (4.6) | 26 (3.6) | 42 (5.4) | ||
| Missing | 10 | |||||||
|
Change in intention (pre- to
post-info) | ||||||||
| No change/Increase in intention | 2112 (93.4) | 1207 (91.9) | 905 (95.5) | χ2(1)=11.6, | 689 (91.3) | 695 (94.9) | 728 (93.9) | χ2(2)=8.8, |
| Decrease in intention | 150 (6.6) | 107 (8.1) | 43 (4.5) | P=0.001 | 66 (8.7) | 37 (5.1) | 47 (6.1) | P=0.01 |
| Missing | 10 | |||||||
|
Objective understanding of
overdiagnosisa | ||||||||
| Correct | 1283 (56.7) | 784 (59.7) | 499 (52.5) | χ2(1)=11.8, | 436 (57.8) | 411 (55.9) | 436 (56.3) | χ2(2)=0.6, |
| Incorrect/don't know | 981 (43.3) | 529 (40.3) | 452 (47.5) | P=0.001 | 318 (42.2) | 324 (44.1) | 339 (43.7) | P=0.73 |
| Missing | 8 | |||||||
|
Subjective understanding of
overdiagnosisb | ||||||||
| Any uncertainty | 802 (35.6) | 497 (38.0) | 305 (32.4) | χ2(1)=7.5, | 256 (34.3) | 266 (36.2) | 280 (36.3) | χ2(2)=0.8, |
| No uncertainty | 1449 (64.4) | 812 (62.0) | 637 (67.6) | P=0.006 | 490 (65.7) | 468 (63.8) | 491 (63.7) | P=0.66 |
| Missing | 21 | |||||||
Significant group differences are shown in bold
Samples sizes vary slightly between analyses due to missing data.
a
Response to the question: who do you think is more likely to be diagnosed with breast cancer? Women who have screening mammograms (correct) or women who do not have screening mammograms (incorrect).
b
Derived from three items assessing ease of understanding, confidence in having made sense of the information and knowing how to interpret the information; see Supplementary File 2 for wording and coding details.