Table 2.
Comparison of different cut-off point (CP) schemes for classifying Numeric Rating Scale (NRS) scores as mild, moderate or severe pain in terms of interference with functioning: F-value in ANOVA using the CP scheme as independent variable and the Pain Disability Index (PDI) scores as dependent variables, for all patients and for the subgroups with low and high catastrophizing tendency (i.e., Pain Catastrophizing Scale (PCS) scores ≤ or > the median of the scores, 29).
| CP 3,6 | CP 3,7 | CP 4,5 | CP 4,6 | CP 4,7 | CP 4,8 | CP 5,6 | CP 5,7 | CP 5,8 | CP 5,9 | CP 6,7 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ALL PATIENTS (N = 2854) | |||||||||||
| CP scheme–PDI | 332.63 | 306.15 | 317.17 | 337.60 | 334.67 | 253.48 | 337.63 | 369.65 | 324.08 | 306.96 | 291.35 |
| Ranking | 5 | 3 | 4 | 2 | 1 | 6 | |||||
| PATIENTS WITH PCS TOTAL SCORE ≤ 29 (N = 1461) | |||||||||||
| CP scheme–PDI | 173.14 | 140.30 | 163.10 | 172.20 | 152.79 | 122.50 | 170.00 | 172.34 | 157.38 | 154.46 | 136.35 |
| Ranking | 1 | 5 | 3 | 4 | 2 | 6 | |||||
| PATIENTS WITH PCS TOTAL SCORE > 29 (N = 1385) | |||||||||||
| CP scheme–PDI | 124,57 | 129.58 | 121.62 | 130.02 | 143.46 | 101.41 | 132.35 | 156.76 | 130.55 | 121.63 | 123.61 |
| Ranking | 6 | 5 | 2 | 3 | 1 | 4 | |||||
Rankings are given below the F-values, from the highest (1) to the lowest (6) rank.
CP: cut-off points, figures refer to highest scores in the first and second categories, for example CP 4,7 means a CP scheme where the first category includes the NRS scores 1–4, the second category NRS 5–7 and the third category NRS 8–10.