Table 2.
Crude and adjusted odds ratios of being diagnosed with colorectal cancer by screening status and Duke stage
| Invitational status—screening status | Main analysisa |
Sensitivity analysis 1–known stage onlyb |
Sensitivity analysis 2– inverse probability weighting |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Controlsc | Cases | OR (95% CI) | cORd (95% CI) | Controlsc | Cases | OR (95% CI) | cORd (95% CI) | Controlsc | Cases | OR (95% CI) | cORd (95% CI) | ||
| All stages, No. | 29 036 | 14636 | 21 779 | 10979 | 29 036 | 14636 | |||||||
| Invited—unscreened | 40.3% | 40.3% | 1.00 (Referent) | 1.00 (Referent) | 40.4% | 38.0% | 1.00 (Referent) | 1.00 (Referent) | 40.3% | 40.3% | 1.00 (Referent) | 1.00 (Referent) | |
| Invited—screened | 59.7% | 59.7% | 1.00 (0.96 to 1.04) | 1.00 (0.89 to 1.15) | 59.6% | 62.0% | 1.11 (1.06 to 1.17) | 1.12 (0.98 to 1.28) | 59.7% | 59.7% | 1.00 (0.96 to 1.04) | 1.00 (0.89 to 1.15) | |
| Stage Duke B or worse, No.e | 22 702 | 11441 | 17 557 | 8847 | 12 356 | 6231 | |||||||
| Invited—unscreened | 40.0% | 44.2% | 1.00 (Referent) | 1.00 (Referent) | 40.3% | 40.7% | 1.00 (Referent) | 1.00 (Referent) | 41.0% | 50.3% | 1.00 (Referent) | 1.00 (Referent) | |
| Invited—screened | 60.0% | 55.8% | 0.83 (0.80 to 0.88) | 0.89 (0.76 to 1.03) | 59.7% | 59.3% | 0.98 (0.93 to 1.04) | 1.05 (0.90 to 1.22) | 59.0% | 49.7% | 0.68 (0.63 to 0.74) | 0.73 (0.62 to 0.85) | |
| Duke C or worse, No. | 13 909 | 7014 | 10 884 | 5489 | 10 023 | 5059 | |||||||
| Invited—unscreened | 40.4% | 47.0% | 1.00 (Referent) | 1.00 (Referent) | 41.0% | 42.2% | 1.00 (Referent) | 1.00 (Referent) | 41.2% | 50.2% | 1.00 (Referent) | 1.00 (Referent) | |
| Invited—screened | 59.6% | 53.0% | 0.76 (0.72 to 0.81) | 0.81 (0.70 to 0.94) | 59.0% | 57.8% | 0.95 (0.89 to 1.02) | 1.01 (0.87 to 1.19) | 58.8% | 49.8% | 0.69 (0.63 to 0.75) | 0.74 (0.62 to 0.87) | |
| Duke D, No. | 6622 | 3340 | 3597 | 1815 | 5448 | 2750 | |||||||
| Invited—unscreened | 40.4% | 57.7% | 1.00 (Referent) | 1.00 (Referent) | 41.8% | 52.0% | 1.00 (Referent) | 1.00 (Referent) | 41.3% | 54.2% | 1.00 (Referent) | 1.00 (Referent) | |
| Invited—screened | 59.6% | 42.3% | 0.49 (0.45 to 0.53) | 0.68 (0.50 to 0.93) | 58.22% | 47.99% | 0.66 (0.58 to 0.74) | 0.92 (0.66 to 1.27) | 58.7% | 45.8% | 0.59 (0.52 to 0.66) | 0.82 (0.59 to 1.13) | |
a
Individuals with suspected Duke D are assumed to be Duke D. B+ NOS = Duke B or worse not otherwise specified; CI = confidence interval; OR = odds ratio.
b
This analysis equates to assuming stage is missing completely at random.
c
Percentages of disease-free controls matched to cases of the relevant stage.
d
Corrected for self-selection: 1.00 for all stages, 1.04 up to Duke C or worse, and 1.20 for Duke D.
e
Duke B or worse always includes those with stage recorded as Duke B+ NOS, but Duke C or worse always excludes them.