The final predictive models* of clinically important improvement in chronic disabling neck pain with PGICS and NDI as outcome
| Prognostic factor | β | SE | OR | 95% CI | P value | Sβ |
| PGICS (89/263)† | ||||||
| Neck disability | 0.08 | 0.04 | 1.08 | 1.01 to 1.16 | 0.03 | 0.06 |
| Age | −0.08 | 0.05 | 0.92 | 0.84 to 1.01 | 0.08 | −0.06 |
| AUC (95% CI)‡ | 0.64 (0.55 to 0.73) | |||||
| NDI (88/259)† | ||||||
| Neck disability | 0.08 | 0.03 | 1.08 | 1.02 to 1.14 | 0.01 | 0.05 |
| Depression | −0.11 | 0.05 | 0.89 | 0.81 to 0.98 | 0.02 | −0.07 |
| Catastrophising | ||||||
| 3 months | 0.07 | 0.06 | 1.08 | 0.96 to 1.21 | 0.21 | 0.05 |
| 15 months | −0.09 | 0.06 | 0.92 | 0.82 to 1.03 | 0.14 | −0.06 |
| x time§ | −0.01 | 0.01 | 0.99 | 0.97 to 1.00 | 0.03 | −0.01 |
| AUC (95% CI)‡ | 0.67 (0.59 to 0.75) | |||||
An OR>1 reflects a higher odds of clinical important improvement and an OR<1 reflects a lower odds of clinical important improvement.
The intercept (β0) for the PGICS model was 1.27, and for the NDI model −1.89.
*Data from all three follow-ups (3, 9 and 15 months) were used in the models.
†Number of participants in the analysis/number of outcome observations in the analysis.
‡Internally validated receiver operating characteristics curve (AUC) with 95% CI.
§Effect measure modification term in the model (catastrophising x time).
β, beta-coefficient; NDI, normalised Neck Disability Index; PGICS, Patient Global Impression of Change Scale; Sβ, shrinkage corrected beta-coefficient (shrinkage factor x β).