Table 5.
Validation of prediction model
| Risk category | Low | Intermediate | High |
|---|---|---|---|
|
Original study group |
|
|
|
|
N=282 n (% of N) |
91 (32) |
86 (31) |
105 (37) |
|
Risk for ‘initial U-RTW’1 predicted by final model % (95% CI) |
7.2 (3.2-15.3) |
19.3 (11.8-29.3) |
34.9 (25.2-46.1) |
|
Observed number: obn obn/n |
7/91 |
18/86 |
39/105 |
|
Observed risk % |
7.7 |
20.9 |
37.1 |
|
Risk for ‘one-year U-RTW’2 |
9.1 (4.3-18.1) |
33.5 (23.4-45.3) |
60.6 (49.3-71.0) |
|
predicted by final model % (95% CI) | |||
|
Observed number: obn obn/n |
9/91 |
29/86 |
62/105 |
|
Observed risk % |
10.2 |
33.7 |
59.1 |
|
Validation study group |
|
|
|
|
N=104 n (% of N) |
27 (26) |
26 (25) |
51 (49) |
|
‘Initial U-RTW’1, observed number: obn obn/n |
3/27 |
5/26 |
20/51 |
|
Observed risk % |
11.1 |
19.2 |
39.2 |
|
‘One-year U-RTW’2, observed number obn/n |
7/27 |
7/19 |
30/59 |
| Observed risk % | 25.9 | 38.5 | 58.8 |
Upper panel: Predicted risks with 95% confidence intervals for unsuccessful return to work (U-RTW) and corresponding observed risks in the original study group.
Lower panel: Observed risks for U-RTW in the validation study group.
1 Not succeeding in working continuously for at least 4 weeks work during the first year after inclusion or registered as unemployed for at least 4 weeks.
2 Not succeeding in working continuously for at least 4 weeks up to the one-year date or registered as unemployed for at least 4 weeks up to the one-year date.
The figures apply for patients with non-specific LBP and patients with radiculopathy who were middle aged (~40 years) and with BMI ~25. Predicted risks for patients with radiculopathy, who were older and/or obese were higher (not shown because of few patients in subgroups, see article text “Small subgroups..”).
CI: Confidence interval.