Table 5.
Factors predicting walking ability 6 weeks, 6 months and 12 months following surgery – multivariate analysis
| Pre-operative factors | 6 week following surgery | 6 months following surgery | 12 months following surgery | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI of the OR | P-value | OR | 95% CI of the OR | P-value | OR | 95% CI of the OR | P-value | |
| Age categories | |||||||||
| < 60 | Ref | Ref | Ref | ||||||
| 60–64.5 | 1.17 | (1.03, 1.32) | 0.012 | 1.08 | (1.01, 1.24) | 0.011 | 1.07 | (1.01, 1.24) | 0.021 |
| 65–69.5 | 1.24 | (1.07, 1.45) | 0.004 | 0.95 | (0.82, 0.99) | 0.024 | 1.17 | (1.01, 1.19) | 0.042 |
| 70–74.5 | 1.16 | (0.97, 1.39) | 0.095 | 0.88 | (0.77, 1.39) | 0.095 | 0.99 | (0.76, 1.30) | 0.986 |
| ≥ 75 | 1.62 | (1.28, 2.04) | < 0.001 | 1.34 | (1.11, 1.60) | 0.007 | 1.54 | (1.07, 2.18) | 0.024 |
| Gender | |||||||||
| Female | Ref | Ref | Ref | ||||||
| Male | 0.98 | (0.89, 1.08) | 0.733 | 0.97 | (0.88, 1.07) | 0.580 | 0.99 | (0.88, 1.11) | 0.947 |
| BMI Categories (kg/m2) | |||||||||
| < 20 | Ref | Ref | Ref | ||||||
| 20–24.9 | 0.91 | (0.64, 1.31) | 0.646 | 0.86 | (0.60, 1.24) | 0.442 | 1.06 | (0.93, 1.55) | 0.728 |
| 25–29.9 | 1.05 | (0.74, 1.48) | 0.770 | 0.94 | (0.66, 1.33) | 0.741 | 1.07 | (0.75, 1.54) | 0.685 |
| 30–34.9 | 1.19 | (0.84, 1.71) | 0.322 | 1.08 | (0.75, 1.55) | 0.656 | 1.25 | (0.87, 1.82) | 0.221 |
| 35–39.9 | 1.56 | (1.05, 2.32) | 0.027 | 1.24 | (1.05, 1.87) | 0.015 | 1.52 | (1.00, 2.30) | 0.048 |
| ≥ 40 | 1.39 | (0.85, 2.29) | 0.186 | 1.17 | (1.02, 1.96) | 0.005 | 1.34 | (1.21, 5.23) | 0.015 |
| Maximum walking distance (meters) | 0.99 | (0.99, 1.00) | 0.062 | 1.00 | (1.02, 1.15) | 0.021 | 1.10 | (1.05, 1.25) | 0.027 |
| Time stood (minutes) | 1.00 | (0.98, 1.02) | 0.711 | 1.01 | (0.99, 1.02) | 0.144 | 1.00 | (0.98, 1.02) | 0.501 |
| Neurological deficit | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | 1.05 | (0.95, 1.15) | 0.313 | 1.00 | (0.92, 1.08) | 0.958 | 0.96 | (0.86, 1.07) | 0.475 |
| Presence of comorbidity | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | − 0.07 | (− 0.09, − 0.05) | 0.242 | 1.33 | (0.98, 1.47) | 0.564 | 1.37 | (0.98, 1.67) | 0.089 |
| Work status | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | 1.09 | (0.81, 1.45) | 0.486 | 1.21 | (0.98, 1.47) | 0.064 | 1.26 | (0.97, 1.65) | 0.072 |
| Education | |||||||||
| Up to & including secondary school | Ref | Ref | Ref | ||||||
| Higher education | 0.79 | (0.73, 0.86) | < 0.001 | 0.74 | (0.67, 0.81) | < 0.001 | 0.90 | (0.80, 0.96) | 0.005 |
| Use of analgesia | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | 0.97 | (0.71, 1.34) | 0.856 | 0.97 | (0.71, 1.34) | 0.856 | 0.79 | (0.54, 1.15) | 0.190 |
| Surgery type | |||||||||
| No discectomy | Ref | Ref | Ref | ||||||
| Discectomy | 1.07 | (0.97, 1.18) | 0.156 | 1.25 | (1.11, 1.39) | < 0.001 | 1.14 | (1.03, 1.28) | 0.013 |
| Durations of symptoms (years) | 1.00 | (0.99, 1.01) | 0.082 | 1.00 | (0.99, 1.01) | 0.378 | 1.00 | (0.99, 1.01) | 0.233 |
| Zung depression score | 1.01 | (0.99, 1.03) | 0.171 | 1.00 | (0.98, 1.01) | 0.930 | 1.00 | (0.97, 1.03) | 0.512 |
| Fear avoidance (work) (baseline) | 0.99 | (0.98, 1.01) | 0.748 | 0.99 | (0.97, 1.01) | 0.412 | 0.99 | (0.97, 1.03) | 0.512 |
| Fear avoidance (pain) (baseline) | 0.99 | (0.97, 1.02) | 0.796 | 1.00 | (0.99, 1.01) | 0.136 | 1.00 | (0.97, 1.01) | 0.776 |
| Back pain (NRS) | 1.01 | (0.98, 1.03) | 0.335 | 1.03 | (0.95, 1.12) | 0.156 | 1.00 | (0.98, 1.02) | 0.868 |
| Leg pain (NRS) | 0.96 | (0.93, 0.99) | 0.031 | 1.01 | (1.00, 1.04) | 0.007 | 1.10 | (1.01, 1.21) | 0.046 |
| Quality of life (EQ-5D-5L Health VAS) | 1.00 | (0.99, 1.00) | 0.662 | 1.00 | (0.99, 1.00) | 0.271 | 1.00 | (0.99, 1.00) | 0.145 |
| Quality of life (EQ-5D-5L) | 0.70 | (0.53, 0.93) | 0.016 | 0.72 | (0.53, 0.98) | 0.039 | 0.72 | (0.56, 0.89) | 0.037 |
| Disability (ODI) | 1.01 | (1.01, 1.02) | < 0.001 | 1.01 | (1.01, 1.02) | < 0.001 | 1.01 | (1.01, 1.02) | < 0.001 |
Abbreviations: BMI: body mass index; CI: confidence interval; VAS: visual analogue scale; ODI: Oswestry Disability Index; NRS: numerical rating scale
Bold values represent p < 0.05