Table 2.
Baseline characteristics of randomised participants by compliance status; complier, non-complier or control
| |
Advice plus cognitive behavioural intervention (n = 468) |
||||
|---|---|---|---|---|---|
| |
Control |
Complier |
Non-complier |
Mean difference
*
|
p value
†
|
| (n = 233) | (n = 294) | (n = 174) | (95% CI) | ||
| Age (years) |
54.1 (14.9) |
55.0 (14.3) |
50.5 (14.8) |
4.5 (1.8, 7.2) |
0.001 |
| Sex |
|
|
|
- |
0.694 |
| Female |
142 (60.9%) |
173 (58.8%) |
105 (60.3%) |
|
|
| Male |
90 (38.6%) |
121 (41.2%) |
68 (39.1%) |
||
| Missing |
1 (0.4%) |
0 |
1 (0.6%) |
||
| Ethnic origin |
- |
0.258 |
|||
| White |
206 (88.4%) |
268 (91.2%) |
144 (82.8%) |
|
|
| Mixed |
3 (1.3%) |
2 (0.7%) |
2 (1.1%) |
||
| Asian |
8 (3.4%) |
9 (3.1%) |
12 (6.9%) |
||
| Black |
4 (1.7%) |
4 (1.4%) |
3 (1.7%) |
||
| Chinese |
1 (0.4%) |
1 (0.3%) |
0 |
||
| Missing |
11 (4.7%) |
10 (3.4%) |
13 (7.5%) |
||
| Severity of back pain |
|
|
|
- |
0.802 |
| Moderately troublesome |
130 (55.8%) |
157 (53.4%) |
95 (54.6%) |
|
|
| Very or extremely troublesome |
103 (44.2%) |
137 (46.6%) |
79 (45.4%) |
|
|
| Age left full-time education (years) |
- |
0.584 |
|||
| ≤16 |
121 (51.9%) |
168 (57.1%) |
98 (56.3%) |
|
|
| 17-19 |
61 (26.2%) |
65 (22.1%) |
39 (22.4%) |
|
|
| ≥20 |
49 (17.2%) |
48 (16.3%) |
25 (14.4%) |
|
|
| Still in full-time education |
2 (0.9%) |
0 |
1 (0.6%) |
|
|
| Missing |
9 (3.9%) |
13 (4.4%) |
11 (6.3%) |
|
|
| In employment† |
- |
0.612 |
|||
| Yes |
110 (47.2%) |
147 (50.0%) |
91 (52.3%) |
|
|
| No |
122 (52.4%) |
146 (49.7%) |
82 (47.1%) |
|
|
| Retired |
77 (63.1%) |
94 (64.4%) |
36 (43.9%) |
|
|
| At home not looking for work |
4 (3.3%) |
12 (8.2%) |
13 (15.9%) |
|
|
| Unable to work because of back pain |
11 (9.0%) |
12 (8.2%) |
10 (12.2%) |
|
|
| Unable to work because of other illness |
9 (7.4%) |
10 (6.8%) |
6 (7.3%) |
|
|
| Unemployed and looking for work |
8 (6.6%) |
1 (0.7%) |
3 (3.7%) |
|
|
| In full-time education |
2 (1.6%) |
0 |
0 |
|
|
| Other |
3 (2.5%) |
1 (0.7%) |
5 (6.1%) |
|
|
| Reason not given |
8 (6.6%) |
16 (11.0%) |
9 (11.0%) |
|
|
| Duration of back pain (years since first onset) |
13.2 (12.7) |
14.1 (14.2) |
11.4 (11.2) |
2.8 (0.2, 5.3) |
0.034 |
| Frequency of back pain (past 6 weeks) |
- |
0.009 |
|||
| Everyday |
162 (69.5%) |
189 (64.3%) |
126 (72.4%) |
|
|
| Less often than everyday |
47 (20.2%) |
82 (27.9%) |
29 (16.7%) |
||
| Missing |
24 (10.3%) |
23 (7.8%) |
19 (10.9%) |
||
| Roland Morris questionnaire |
8.5 (4.7) |
8.6 (4.9) |
9.1 (5.2) |
-0.4 (-1.4, 0.5) |
0.357 |
| Modified Von Korff disability |
46.2 (23.8) |
47.0 (23.6) |
51.0 (24.1) |
-4.0 (-8.6, 0.5) |
0.083 |
| Modified Von Korff pain |
59.4 (19.5) |
57.6 (19.3) |
62.2 (18.9) |
-4.6 (-8.2, -1.0) |
0.014 |
| EQ-5D | 0.6 (0.3) | 0.6 (0.3) | 0.5 (0.3) | 0.1 (-0.01, 0.1) | 0.082 |
Data are mean (SD) or n (%). Participants in the control group were assigned to receive advice only.
*Mean difference between compliers and non-compliers in cognitive behavioural intervention arm.
†Reported p values are from t test where mean differences are reported and chi-squared tests elsewhere.