Background
Methods
Selection of potential prognostic Factors/Independent variables
Best-evidence synthesis methods to identify prognostic factors
Summary of the systematic review on prognostic factors
Prognostic factors identified from Phase III studies
Prognostic factors identified from phase I and II studies
Other prognostic factors
Development and Internal Validation: the Saskatchewan dataset
Replicating: repeating the Models in the Ontario dataset
Outcomes
Primary outcome: self-reported global recovery
Secondary outcomes: claim Closure
Analysis
Univariate Associations
Multivariable analysis
Development of the Prediction Model
Internal validation of the Prediction Model
Repeating the Prediction Models in the Ontario Population
Province | |||
---|---|---|---|
Baseline Prognostic Factors | Saskatchewan | Ontario | Phase of evidence* |
(N = 4917) | (N = 340) | ||
Age in years [mean (s.d.)] | 38.3 (15.1) | 40.5 (13.2) | I, II |
Female [frequency (%)] | 3263 (66.3%) | 229 (67.3%) | I, II |
Married or common law | 2638 (53.6%) | 184 (54.0%) | n/a |
Employed (paid employment) | 4138 (84.1%) | 286 (84.1%) | I, II |
Average Neck Pain [mean (s.d.)] | 6.5 (2.1)# | 5.7 (2.1) | I, II |
Average Low Back Pain [mean (s.d.)] | 3.8 (3.5)## | 4.2 (3.3) | |
CES-D scores [mean (s.d.)] | 16.3 (12.0)### | 15.4 (12.6) | n/a |
Depression (> 27 points on CES-D) [frequency (%)]) | 984 (20.0%) | 60 (17.7%) | I, II, III |
Prior Neck Injury [frequency (%)] | 1156 (23.6%) | 2 (0.59)+ | III |
Post collision anxiety or worry [frequency (%)] | 2149 (43.7%) | 210 (62.0%) | I, II, III |
Disability [frequency (%)] | 3769 (76.6%) | I, II | |
Whiplash Disability Questionnaire [mean (s.d.)] | 54.8 (29.3) | I, II | |
Concentration Problems [frequency (%)] | 1221 (24.8%) | 121 (35.6%) | n/a |
Percent of Body in Pain [mean (s.d.)] | 23.6 (15.7) | n/a++ | n/a |
Muscle, bone or joint problems++ [frequency (%)] | n/a | ||
Doesn’t have it | 197 (57.1) | ||
None or mild effect on life | 118 (34.7) | ||
Moderate or severe effect on life | 28 (8.2) | ||
Expectations of recovery [frequency (%)] | (5 missing values) | I, II, III | |
Get better soon | 1224 (24.9%) | 165 (48.5%) | |
Get better slowly | 2060 (41.9%) | 101 (29.7%) | |
Never get better | 90 (1.8%) | 3 (0.9%) | |
Don’t know | 1539 (31.3%) | 71 (20.9%) | |
Days since injury [median (range)] | 9.0 (0–21) | 6.0 (0–25) | none |
Results
Descriptive statistics
Univariable Associations
Multivariable analysis
Time-to-recovery
Stage 1: prediction model with phase III prognostic factors
Modeling Stage | Predictive Model | Phase of prognostic factor evidence | Time to recovery C-statistic (95% CI) | Time to claim closure C-statistic (95% CI) |
---|---|---|---|---|
Development | Stage 1 | Phase III | 0.626 (0.617, 0.636) | 0.598 (0.588, 0.607) |
Stage 2 | Phase I-III | 0.644 (0.634, 0.653) | 0.636 (0.626, 0.645) | |
Internal Validation (Bootstrapped models) | Stage 1 | Phase III | 0.626 (0.617, 0.636) | 0.598 (0.588, 0.600) |
Stage 2 | Phase I-III | 0.644 (0.634, 0.653) | 0.636 (0.626, 0.645) | |
External validation in Ontario | Stage 2 | Phase I-III | 0.654 (0.617, 0.692) | 0.580 (0.539, 0.621) |
Stage 1 | Stage 2 | |||
---|---|---|---|---|
Baseline prognostic factor | HR (95% CI) | HR (95% CI) | ||
Age in years | - | 0.993 (0.99, 0.99) | ||
Prior neck injury claim with SGI | 0.68 (0.63, 0.74) | 0.72 (0.66, 0.78) | ||
Post-collision Anxiety or Worry | 0.89 (0.83, 0.95) | - | ||
Depression as > 27 on CES-D | 0.85 (0.78, 0.93) | - | ||
Pain Drawing - Percentage | - | 0.99 (0.99, 0.99) | ||
Neck pain intensity (NRS) | - | 0.93 (0.92, 0.95) | ||
Headache intensity (NRS) | - | 0.98 (0.97, 0.99) | ||
Disability | - | 0.92 (0.85, 0.99) | ||
Expectations of recovery | ||||
Never get better | 0.25 (0.18, 0.35) | 0.28 (0.20, 0.40) | ||
Get better slowly | 0.66 (0.61, 0.72) | 0.72 (0.67, 0.78) | ||
Don’t know | 0.43 (0.40, 0.47) | 0.49 (0.45, 0.54) |
Stage 2: prediction models with phase I and II prognostic factors
Stage 3: prediction models with clinically relevant prognostic factors
The final model
Time-to-recovery
Time-to-claim-closure
Stage 1 | Stage 2 | ||
---|---|---|---|
Baseline prognostic factor | HR (95% CI) | HR (95% CI) | |
Age in years | - | 0.999 (0.99, 0.99) | |
Prior neck injury claim with SGI | 0.71 (0.66, 0.77) | 0.776 (0.72, 0.84) | |
Post-collision Anxiety or Worry | 0.85 (0.80, 0.91) | - | |
Depression as > 27 on CES-D | 0.82 (0.75, 0.90) | 0.99 (0.99, 0.99) | |
Pain Drawing - Percentage | - | 0.97 (0.96, 0.99) | |
Neck pain intensity (NRS) | - | 0.98 (0.97, 0.99) | |
Headache intensity (NRS) | - | 0.78 (0.72, 0.85) | |
Disability | - | 0.91 (0.84, 1.00) | |
Expectations of recovery | |||
Never get better | 0.36 (0.26, 0.50) | 0.41 (0.30, 0.58) | |
Get better slowly | 0.74 (0.68, 0.80) | 0.82 (0.76, 0.89) | |
Don’t know | 0.56 (0.51, 0.61) | 0.64 (0.59, 0.71) |