Table 2.
Characteristics of patients with low back pain and of patients who also have leg pain or signs of nerve root involvement
| |
All subgroups |
Local LBP only |
LBP + pain above knee |
LBP + pain below knee |
LBP + signs of nerve root involvement |
p-values |
|---|---|---|---|---|---|---|
| n = 2,673 | n = 437 | n = 398 | n = 807 | n = 1,031 | Significant pair-wise comparisons | |
|
Females, (95% CI) |
56% (54%-58%) |
49% (44%-54%) |
59% (54%-64%) |
60% (57%-64%) |
54% (51%-57%) |
p < .01 local vs. above local vs. below below vs. NRI |
|
Age in years, median (IQR) |
47 (36-58) |
43 (32-55) |
46 (35-58) |
50 (39-63) |
46 (37-58) |
p < .001 local vs. all below vs. all |
|
Duration*, (95% CI) 0 – 3 months |
18% (16%-19%) |
8% (6%-11%) |
13% (10%-16%) |
15% (12%-17%) |
27% (24%-29%) |
p < .001 local vs. below NRI vs. all |
|
3 – 12 months |
34% (32%-36%) |
34% (30%-39%) |
36% (31%-41%) |
35% (31%-38%) |
35% (32%-38%) |
|
|
> 12 months |
45% (44%-47%) |
57% (53%-62%) |
51% (46%-56%) |
51% (47%-54%) |
38% (35%-41%) |
|
|
Previous episodes, (95% CI) |
74% (73%-76%) |
67% (62%-71%) |
77% (72%-80%) |
76% (72%-79%) |
79% (76%-81%) |
p < .01 local vs. all |
|
Pain irritability, (95% CI) |
74% (72%-76%) |
60% (53%-66%) |
73% (67%-78%) |
76% (72%-80%) |
79% (75%-82%) |
p < .001 local vs. all |
|
LBP intensity, median (IQR) |
6 (5-8) |
5 (4-7) |
6 (4-7) |
6 (4-8) |
6 (5-8) |
p < .001 all comparisons except above vs. below |
|
Leg pain intensity, median (IQR) |
3 (5-7) |
0 (0-0) |
4 (3-6) |
6 (4-7) |
6 (5-8) |
p < .001 all comparisons |
|
Severe leg pain, (95% CI) |
70% (68%-72%) |
0 (0-0) |
68% (64%-73%) |
85% (82%-87%) |
88% (86%-90%) |
p < .001 all comparisons |
|
Dominating leg pain, (95% CI) |
29% (27%-31%) |
0 (0-0) |
23% (18%-27%) |
36% (32%-39%) |
38% (35%-41%) |
p < .001 all comparisons except NRI vs. below |
|
Activity limitation, median (IQR) |
65 (43-83) |
48 (26-67) |
57 (39-74) |
65 (43-78) |
74 (52-87) |
p < .001 all comparisons |
|
Regular employment
§
(95% CI) |
66% (64%-68%) |
77% (73%-82%) |
65% (60%-71%) |
62% (58%-66%) |
66% (63%-70%) |
p = .01 local vs. all |
|
Any sick leave in last 3 months
#
, (95% CI) |
49% (46%-51%) |
41% (35%-47%) |
44% (36%-52%) |
47% (41%-52%) |
56% (52%-61%) |
P <.001 NRI vs. all |
|
Sick leave days in last three months
#
, median (IQR) |
14 (5 – 30) |
10 (4 – 25) |
10 (5 – 21) |
14 (5 – 34) |
18 (7-34) |
< .01 local vs. below local vs. NRI |
|
Depressive symptoms, (95% CI) |
17% (16%-19%) |
12% (9%-15%) |
16% (12%-19%) |
16% (14%-19%) |
21% (18%-23%) |
p < .001 local vs. below NRI vs. all |
|
Fear of movement, (95% CI) |
19% (18%-21%) |
15% (12%-19%) |
16% (12%-19%) |
18% (16%-22%) |
23% (20%-25%) |
P=.06 NRI vs. all |
|
General health, median (IQR) |
50 (30-70) |
53 (40-75) |
50 (33-70) |
50 (30-67) |
48 (29-64) |
p < .001 local vs. all above vs. NRI |
| Directional preference, ¤ (95% CI) | 36% (33%-39%) | 19% (13%-25%) | 32% (24%-39%) | 31% (26%-37%) | 49% (44%-54%) | p < .001 all comparisons except above vs. below |
95% CI = 95% confidence interval; IQR = inter quartile range; NRI = Nerve root involvement signs.
*Does not sum to 100% because of missing values.
#Proportion of patients in regular employment.
¤Proportion of patients with a test conclusion n=1,012(38%)/159(36%)/168(42%)/283(35%)/402(39%.)