Baseline characteristics of the patients according to completion of study
| Characteristics | Complete (n=8) | Incomplete (n=7) | Z-test statistic | p Value |
|---|---|---|---|---|
| Age (years) | 56.5 (45–68) | 64 (53–66) | −1.102 | 0.296 |
| Gender (male/female) | 6/2 | 2/5 | 0.132 | |
| Duration of therapy (months) | 25 (15–88) | 27 (12–180) | −0.081 | 0.960 |
| Preimplant oral morphine dose (mg/day) | 60 (20–120) | 60 (40–240) | −0.241 | 0.869 |
| Morphine dose (mg/day) | 3.065 (1.02–5.65) | 1.6 (0.62–5.5) | −1.273 | 0.232 |
| Adjuvant intrathecal medication (yes/no) | 5/3 | 4/3 | 1.000 | |
| Bupivacaine dose (mg/day) | 2.5 (1.7–4.25) | 2.085 (1.86–2.12) | −0.735 | 0.556 |
| Visual analogue scale | 44.5 (0–69) | 54 (23–64) | −0.522 | 0.632 |
| Oswestry Disability Index | 53 (12–64) | 57.7 (42–72) | −1.222 | 0.244 |
| Hospital Anxiety and Depression (HAD) scale | ||||
| HAD anxiety | 7 (2–16) | 8 (1–12) | −0.116 | 0.934 |
| HAD depression | 9 (2–15) | 7 (2–12) | −0.816 | 0.447 |
| Coping Strategies Questionnaire | ||||
| Diverting attention | 12 (0–29) | 13 (0–31) | −0.501 | 0.649 |
| Reinterpreting pain sensation | 0 (0–19) | 3.5 (0–26) | −0.466 | 0.714 |
| Catastrophising | 22 (2–31) | 15 (1–27) | −0.575 | 0.608 |
| Ignoring pain sensations | 8 (0–21) | 8 (0–28) | −0.215 | 0.861 |
| Praying or hoping | 15 (2–30) | 18.5 (0–25) | −0.358 | 0.760 |
| Coping self-statements | 24 (13–30) | 19 (2–32) | −0.358 | 0.755 |
| Increasing activity level | 16 (3–30) | 13.5 (6–29) | −0.143 | 0.916 |
| Control over pain | 2 (1–5) | 3.5 (2–4) | −1.101 | 0.317 |
| Ability to decrease pain | 2 (1–4) | 3 (2–4) | −1.050 | 0.386 |
| Cognitive coping and suppression | 32 (12–70) | 32.5 (6–83) | −0.000 | 1.000 |
| Helplessness | −5 (−14 to 11) | 0 (−36 to 10) | −0.215 | 0.868 |
| Diverting attention and praying/hoping | 27 (2–54) | 31.5 (0–56) | −0.287 | 0.809 |
Median (minimum–maximum); gender and adjuvant intrathecal medication were evaluated using Fisher's exact test; all other variables analysed using the Mann-Whitney U test (Exact sig. (2-tailed)); statistical significance represented at p<0.05.