Table 2.
Results from the multivariable analyses of recovery from WAD a , c-index and internally validated c-index (n=680)
| Prognostic factors | Model 1 a (n=679) b | Model 2 a (n=648) b | Final model 3 a (n=633) b | ||
|---|---|---|---|---|---|
| |
β (SE) |
β (SE) |
β (SE) |
HRR (95% CI) |
p-value |
|
Age |
-0.01 (0.00) |
-0.01 (0.00) |
-0.01 (0.00) |
0.99 (0.98, 1.00)* |
0.002 |
|
Education | |||||
| < Grade 8** |
0.0 |
0.0 |
- |
- |
- |
| Grade 8 |
0.21 (0.28) |
0.23 (0.28) |
- |
- |
- |
| High school |
0.51 (0.27) |
0.48 (0.27) |
- |
- |
- |
| Post-secondary school |
0.28 (0.27) |
0.29 (0.27) |
- |
- |
- |
| Technical school |
0.41 (0.28) |
0.31 (0.28) |
- |
- |
- |
| University |
0.69 (0.28) |
0.59 (0.28) |
- |
- |
- |
|
No. of days to reporting the collision |
|
-0.02 (0.01) |
-0.02 (0.01) |
0.98 (0.97, 0.99) |
≤0.001 |
|
Neck pain intensity
c
| |||||
| Mild** |
|
0.0 |
0.0 |
1.0 |
|
| Moderate |
|
-0.48 (0.14) |
-0.43 (0.14) |
0.65 (0.50, 0.85) |
0.002 |
| Severe |
|
-0.70 (0.15) |
-0.50 (0.15) |
0.61 (0.45, 0.82) |
0.001 |
|
Low back pain intensity
c
| |||||
| No pain** |
|
0.0 |
0.0 |
1.0 |
|
| Mild |
|
-0.01 (0.16) |
0.17 (0.15) |
1.19 (0.88, 1.61) |
0.26 |
| Moderate |
|
-0.29 (0.12) |
-0.16 (0.12) |
0.85 (0.68, 1.07) |
0.17 |
| Severe |
|
-0.46 (0.15) |
-0.41 (0.15) |
0.66 (0.49, 0.89) |
0.01 |
|
Pain other than neck and back pain | |||||
| No** |
|
0.0 |
0.0 |
1.0 |
|
| Yes |
|
-0.38 (0.11) |
-0.35 (0.11) |
0.71 (0.57, 0.88) |
0.002 |
|
Musculoskeletal problem before collision
d
| |||||
| Absent** |
|
0.0 |
- |
- |
- |
| No/Mild |
|
-0.03 (0.12) |
- |
- |
- |
| Severe |
|
-0.33 (0.18) |
- |
- |
- |
|
Headache before collision | |||||
| Absent** |
|
0.0 |
0.0 |
1.0 |
|
| No/Mild |
|
0.32 (0.11) |
0.28 (0.11) |
1.32 (1.07, 1.63) |
0.01 |
| Severe |
|
-0.01 (0.15) |
-0.03 (0.15) |
0.97 (0.72, 1.31) |
0.87 |
|
MD visits since collision
e
| |||||
| 1** |
|
0.0 |
- |
- |
- |
| 2 |
|
-0.05 (0.11) |
- |
- |
- |
| ≥ 3 |
|
-0.26 (0.13) |
- |
- |
- |
|
Recovery expectations
f
| |||||
| Better soon** |
|
|
0.0 |
1.0 |
|
| Better slowly/Never better |
|
|
-0.66 (0.12) |
0.51 (0.41, 0.65) |
≤0.001 |
| Don′t know |
|
|
-1.09 (0.14) |
0.34 (0.26, 0.44) |
≤0.001 |
|
C-index (95% CI) |
0.56 (0.53, 0.59) |
0.65 (0.63, 0.68) |
0.68 (0.65, 0.71) |
||
| Internal validated c-index (95% CI) | 0.55 (0.51, 0.58) | 0.63 (0.59, 0.66) | 0.67 (0.63, 0.70) | ||
Note: Overall Goodness of fit for the final model was adequate according to the Cox-Snell residual plot and the score test (p= 0.66).
* 95% CI: 0.984, 0.996.
** Reference category.
a Cox proportional hazard regression: Model 1: Result from including socio-demographics related factors in the backward selection process. Model 2: Result using prognostic factors remaining from model 1 plus factors related to collision, symptoms, comorbidity and health care. Final model 3: Result using prognostic factors remaining from model 2 plus factors related to general health and psychology.
b Numbers of subjects are less than the study population (n=680) due to missing answer for prognostic factors in the backward selection procedures.
c 11 point numeric rating scale (NRS) were 0 = no pain at all and 10 = pain as bad as it could be. Mild: 1-4, Moderate: 5-7, Severe: 8-10.
d The effect on health from muscle, bone or joint problems within 6 months before the collision.
e MD: Medical doctor.
f The answer to the “question”: “Do you think that your injury will…”.