Reduced model B: the variables at second consultation predicting surgery (multiple logistic regression analysis with eventual surgery as dependent variable)
| Baseline predictors of surgery | Crude odds ratio | 95% CI | Adjusted odds ratio | 95% CI |
| History/questionnaire: | ||||
| Duration of disease at presentation: | ||||
| 15–30 days | 3.4 | 1.3–8.7 | 5.8 | 2.7–12.5 |
| More than 30 days | 1.8 | 0.7–5.1 | 1.2 | 0.6–2.7 |
| Previous episodes of pain in the leg | 1.0 | 0.4–2.3 | 0.17 | 0.08–0.3 |
| Previous episodes of low back pain | 2.8 | 0.9–2.1 | 7.3 | 2.8–19.2 |
| Positive family history for: | ||||
| Pain in the back | 3.3 | 0.9–12.4 | 10.1 | 3.2–31.2 |
| Pain in the leg | 1.0 | 0.4–0.9 | 4.1 | 1.9–8.7 |
| Mentally demanding job | 3.8 | 1.7–8.6 | 4.4 | 2.3–8.2 |
| Paraesthesias | 0.5 | 0.2–1.2 | 0.2 | 0.08–0.36 |
| Pain worsening on sitting after 2 weeks | 4.4 | 0.6–2.3 | 24.3 | 9.6–62 |
| Change over 2 weeks in VAS of leg pain | 1.05 | 1.02–1.0 7 | 1.058 | 1.040–1.076 |
| PRI-A of McGill pain questionnaire | 1.3 | 1.1–1.4 | 1.35 | 1.22–1.49 |
| Physical examination: | ||||
| Crossed straight leg raising | 2.1 | 0.8–5.7 | 4.2 | 1.8–10.2 |
| Exponential of the intercept | 2.3*10−3 | (5.3*10−4–1.1*10−2) | ||
Footnotes as for table 2.