Table 3. Regression coefficients from the discrete choice experiments for the different tests and attributes.
| Attribute levels | Screening-naive subjects Coefficient | (95%CI) | Previously screened subjects Coefficient | (95%CI) | P-value † |
|---|---|---|---|---|---|
| Screening test (base level ‘no screening’) | |||||
| No screening (reference level) | |||||
| FOBT | −0.18 | (−0.44;0.08) | 0.38 | (0.15;0.62)* | <0.001 |
| Sigmoidoscopy | 0.30 | (0.06;0.54)* | 0.94 | (0.72;1.16)* | <0.001 |
| Colonoscopy | 0.33 | (0.08;0.57)* | 1.05 | (0.84;1.27)* | <0.001 |
| Risk reduction of CRC-related mortality | |||||
| FOBT | |||||
| 3–2.7% (RR 10%) (reference level) | |||||
| 3–2.4% (RR 25%) | 0.19 | (−0.01;0.38) | 0.17 | (-0.01;0.34) | 0.88 |
| 3–1.8% (RR 40%) | 0.78 | (0.54;1.02)* | 0.65 | (0.44;0.87)* | 0.45 |
| Sigmoidoscopy | |||||
| 3.0–1.8% (RR 40%) (reference level) | |||||
| 3.0–1.5% (RR 50%) | 0.10 | (−0.09;0.29) | 0.33 | (0.16;0.50)* | 0.08 |
| 3.0–0.9% (RR 70%) | 0.65 | (0.42;0.89)* | 0.65 | (0.44;0.86)* | 0.97 |
| Colonoscopy | |||||
| 3.0–0.8% (RR 75%) (reference level) | |||||
| 3.0–0.5% (RR 85%) | 0.16 | (−0.03;0.35) | 0.19 | (0.02;0.36)* | 0.79 |
| 3.0–0.1% (RR 95%) | 0.40 | (0.17;0.62)* | 0.41 | (0.20;0.61)* | 0.95 |
| Screening interval | |||||
| FOBT | |||||
| 4 monthly (reference level) | |||||
| Annual | 0.73 | (0.52;0.93)* | 0.64 | (0.44;0.83)* | 0.50 |
| Triennial | 0.96 | (0.72;1.20)* | 0.67 | (0.46;0.89)* | 0.07 |
| Sigmoidoscopy | |||||
| Annual (reference level) | |||||
| 5 yearly | 0.92 | (0.74;1.11)* | 0.55 | (0.39;0.72)* | <0.001 |
| 10 yearly | 1.14 | (0.91;1.37)* | 0.56 | (0.36;0.75)* | <0.001 |
| Colonoscopy | |||||
| Biennial (reference level) | |||||
| 5 yearly | 0.71 | (0.52;0.90)* | 0.56 | (0.39;0.73)* | 0.22 |
| 10 yearly | 0.72 | (0.48;0.95)* | 0.42 | (0.21;0.63)* | 0.06 |
Abbreviations: CI=confidence interval; CRC=colorectal cancer; FOBT=faecal occult blood test; RR=risk reduction.
†P-value describes the difference between screening-naive and previously screened subjects.
*P-value <0.05 compared with the reference level.