Univariate Cox models: predictors of time to MCID achievement.
| Predictor | HR | 95% CI | P |
| Demographics | |||
| Age | 0.99 | 0.97–1.01 | 0.169 |
| BMI | 1.00 | 0.96–1.04 | 0.987 |
| Sex | 1.22 | 0.78–1.90 | 0.375 |
| Non-white race | 0.67 | 0.36–1.27 | 0.223 |
| ASA ≥3 | 0.57 | 0.37–0.88 | 0.011 |
| CCI score | 0.85 | 0.73–0.98 | 0.025 |
| Prior spine surgery | |||
| Laminectomy | 1.02 | 0.61–1.72 | 0.941 |
| Fusion | 0.80 | 0.37–1.73 | 0.566 |
| Procedure type | |||
| PLF | 1.15 | 0.75–1.76 | 0.522 |
| Primary diagnosis | |||
| Pseudarthrosis/hardware failure | 0.69 | 0.17–2.80 | 0.603 |
| Degenerative disc disease | 1.04 | 0.63–1.72 | 0.885 |
| Degenerative spondylolisthesis | 0.98 | 0.63–1.52 | 0.911 |
| Spinal stenosis | 1.10 | 0.57–2.13 | 0.777 |
| Symptom type | |||
| Axial only | 1.28 | 0.62–2.66 | 0.506 |
| Radicular only | 0.86 | 0.40–1.87 | 0.706 |
| Axial and radicular | 0.95 | 0.54–1.66 | 0.862 |
| Symptom frequency | |||
| Constant | 0.63 | 0.37–1.06 | 0.081 |
| Change in symptoms | |||
| Worse | 1.10 | 0.72–1.69 | 0.657 |
| Symptom duration | |||
| >1 y | 0.94 | 0.61–1.44 | 0.772 |
| PROMIS-PF | |||
| Baseline PF | 0.95 | 0.92–0.98 | 0.005 |
| Baseline disability | |||
| Mild (40+) | 0.57 | 0.28–1.13 | 0.109 |
| Moderate (30–40) | 0.88 | 0.56–1.36 | 0.557 |
| Severe (<30) | 1.81 | 1.11–2.95 | 0.017 |
Abbreviations: ASA, American Society of Anesthesiologists Score; BMI, body mass index; CCI, Charlson Comorbidity Index; MCID, minimal clinically important difference; PLF, posterolateral fusion.
Note: Statistically significant values at P < 0.05 are in boldface.