Table 1 Baseline Characteristics of Low Back Pain Patients in Chiropractic and General Practice in Denmark
All Patients Chiropractic Patients n = 947 General Practice Patients n = 324 P Value c
Age (y) a 44 (28-59) 43 (28-59) 46 (27-59) <.01
Female b 47 (45-50) 45 (42-48) 55 (49-60 <.01
Low back pain + leg pain above knee b 87 (84-88) 90 (88-92) 69 (62-75) <.001
Leg pain below knee + nerve root involvement b 13 (12-16) 10 (8-12) 31 (25-38)
Nerve root involvement, no b 96 (95-97) 98 (97-99) 89 (83-92) <.001
Nerve root involvement, yes b 4 (3-5) 2 (1-3) 11 (8-17)
General health, 75% best b 72 (70-75) 77 (74-79) 59 (53-64) <.001
General health, 25% worst b 28 (25-30) 23 (21-26) 41 (36-47)
Expectations, 75% highest b 73 (71-76) 79 (77-82) 55 (49-61) <.001
Expectations, 25% lowest b 27 (24-29) 21 (18-23) 45 (39-51)
Duration of pain < 2 wk b 57 (54-59) 62 (59-66) 39 (33-44) <.001
Duration of pain ≥ 2 wk b 43 (41-46) 38 (34-41) 61 (56-67)
Previous episodes 0-3 b 48 (45-51) 51 (48-55) 38 (32-44) <.001
Previous episodes > 3 b 52 (49-55) 49 (45-52) 62 (56-67)
Not depressed b 85 (83-87) 89 (87-91) 72 (67-77) <.001
Depressed b 15 (13-17) 11 (9-13) 28 (23-33)
No musculoskeletal comorbidity b 83 (81-85) 88 (86-90) 64 (58-70) <.001
Musculoskeletal comorbidity b 17 (15-19) 12 (10-14) 36 (30-42)
Low back pain intensity (numeric rating scale 0-10) a 7 (4-9) 7 (3-9) 7 (4-9) >.01
Activity limitation (Roland-Morris Disability Questionnaire, proportional score 0-100) a 57 (17-83) 52 (17-83) 61 (22-87) <.001

a   Median (10%, 90% centiles).
b   Proportion (95% CI).
c   P value for statistical significance of difference between the 2 settings.