Table 4

The final predictive models* of clinically important improvement in chronic disabling neck pain with PGICS and NDI as outcome

Prognostic factorβSEOR95% CIP value
PGICS (89/263)†
Neck disability0. to
Age− to 1.010.08−0.06
AUC (95% CI)‡0.64 (0.55 to 0.73)
NDI (88/259)†
Neck disability0. to
Depression− to 0.980.02−0.07
 3 months0. to
 15 months− to 1.030.14−0.06
 x time§− to 1.000.03−0.01
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).