Bivariate analysis achievement for VAS back.
| Characteristic | Failed MCID (%) | RR | 95% CI | P valuea |
| Overall | 28.2% | – | – | – |
| Age | ||||
| 18–50 y | 61.8% | Reference | ||
| <50 y | 38.2% | 1.1 | (0.9–1.5) | 0.176 |
| Gender | ||||
| Male | 68.6% | 0.9 | (0.7–1.2) | 0.563 |
| Female | 31.4% | Reference | ||
| BMI | ||||
| <30 kg/m2 | 58.3% | Reference | ||
| ≥30 kg/m2 | 41.7% | 1.1 | (0.9–1.3) | 0.455 |
| Smoking status | ||||
| Nonsmoker | 79.9% | Reference | ||
| Smoker | 20.1% | 1.2 | (0.9–1.6) | 0.103 |
| Diabetes | ||||
| Nondiabetic | 93.8% | Reference | ||
| Diabetic | 6.2% | 1.1 | (0.7–1.7) | 0.806 |
| Ageless CCI | ||||
| <1 | 51.2% | Reference | ||
| ≥1 | 48.3% | 1.4 | (1.1–1.7) | 0.007 |
| ASA score | ||||
| <2 | 32.6% | Reference | ||
| ≥2 | 67.4% | 1.1 | (0.8–1.4) | 0.526 |
| Insurance | ||||
| Non-WC | 61.1% | Reference | ||
| WC | 38.9% | 1.4 | (1.1–1.6) | 0.001 |
| Operative length | ||||
| <50 min | 69.0% | Reference | ||
| ≥50 min | 31.0% | 0.9 | (0.8–1.0) | 0.185 |
| EBL | ||||
| <50 mL | 50.0% | Reference | ||
| ≥50 mL | 50.0% | 1.1 | (0.9–1.3) | 0.411 |
| Operative levels | ||||
| Single | 71.7% | Reference | ||
| Multilevel | 28.3% | 1.4 | (1.2–1.7) | 0.001 |
| Operative technique | ||||
| Laminectomy | 20.1% | 0.9 | (0.7–1.3) | 0.945 |
| Discectomy | - | - | - | - |
| Laminectomy + discectomy | 74.3% | 1.2 | (0.9–1.5) | 0.148 |
| Spinal pathologies | ||||
| HNP | 76.9% | 0.9 | (0.7–1.3) | 0.858 |
| Central stenosis | 63.0% | 1.1 | (0.8–1.3) | 0.508 |
| Foraminal stenosis | 31.7% | 0.9 | (0.7–1.1) | 0.432 |
Boldface indicates statistical significance.
aP value calculated using Poisson regression.
ASA, American Society of Anesthesiologists; BMI, body mass index; CCI, Charlson Comorbidity Index; EBL, estimated blood loss; HNP, herniated nucleus pulposus; RR, relative risk; VAS, visual analog scale; WC, workers’ compensation.