Parsimonious polynomial model versus patient characteristics model variables
| Predictor variables | Polynomial model | Patient characteristics model | ||||
| OR (95% CI) | P values | β coefficient | OR (95% CI) | P values | β coefficient | |
| Model constant | N/A | N/A | −28.15 | N/A | N/A | −10.44 |
| Age, per year | 1.79 (0.88 to 3.93) | 0.110 | 0.5845 | 1.06 (1.02 to 1.11) | 0.005 | 0.05895 |
| Age2, per year2 | 1.00 (0.99 to 1.00) | 0.158 | −0.004026 | N/A | N/A | N/A |
| Gender, female | N/A | N/A | N/A | – | – | – |
| Lung cancer in family | – | – | – | – | – | – |
| Prior diagnosis of cancer | 1.74 (0.88 to 3.02) | 0.062 | 0.5555 | 1.67 (0.84 to 2.87) | 0.082 | 0.5131 |
| Smoking status, active | 1.66 (1.22 to 2.28) | 0.001 | 0.5046 | – | – | – |
| Pack-years, per pack-year | 1.04 (1.02 to 1.07) | <0.001 | 0.03922 | 1.01 (1.00 to 1.01) | 0.001 | 0.008342 |
| Pack-years2, per pack-year2 | 1.00 (1.00 to 1.00) | 0.013 | −1.632×10–4 | N/A | N/A | N/A |
| Smoking duration, per year | – | – | – | 1.03 (1.00 to 1.07) | 0.068 | 0.03260 |
| Quit duration, per year | – | – | – | 0.96 (0.92 to 1.01) | 0.103 | −0.03875 |
| Prior diagnosis of COPD | 1.51 (0.85 to 2.46) | 0.110 | 0.4144 | 1.69 (0.96 to 2.71) | 0.038 | 0.5263 |
| Prior diagnosis of pneumonia | N/A | N/A | N/A | – | – | – |
| Occupational exposure to asbestos | – | – | – | 1.51 (0.78 to 2.56) | .149 | 0.4137 |
| Emphysema on scan | – | – | – | N/A | N/A | N/A |
| Longest nodule diameter, per mm | – | – | – | N/A | N/A | N/A |
| Longest perpendicular diameter, per mm | 1.11 (1.06 to 1.15) | <0.001 | 0.09962 | N/A | N/A | N/A |
| Longest perpendicular diameter2, per mm2 | 1.00 (1.00 to 1.00) | 0.015 | −6.524×10–4 | N/A | N/A | N/A |
| Presence of non-solid nodule | 1.52 (0.92 to 2.42) | 0.077 | 0.4217 | N/A | N/A | N/A |
| Presence of part solid nodule | 2.49 (1.36 to 4.21) | 0.001 | 0.9108 | N/A | N/A | N/A |
| Presence of nodule in upper lobe | 1.60 (1.05 to 2.39) | 0.021 | 0.4685 | N/A | N/A | N/A |
| Presence of spiculated nodule | 2.12 (1.29 to 3.37) | 0.002 | 0.7512 | N/A | N/A | N/A |
| Nodule count per scan, per additional nodule | 1.67 (0.99 to 2.98) | 0.049 | 0.5128 | N/A | N/A | N/A |
| Nodule count per scan2, per additional nodule2 | 0.82 (0.66 to 0.97) | 0.019 | −0.1947 | N/A | N/A | N/A |
The small dash signifies that the variable was included in the initial regression analysis but not in the final model and thus does not have a value in the equation.
N/A, not applicable (was not included in the initial regression analysis).