Table 4.

Prevalence of low back pain at follow-up according to presence of disc degeneration, psychological characteristics at baseline and treatment received.

	LBP in past 4 weeks				LBP on > 14 days in past 4 weeks				Disabling LBP in past 4 weeksa
	n	%	PRb	(95% CI)	n	%	PRb	(95% CI)	n	%	PRb	(95% CI)
Disc degeneration
Absent	86	70	1	-	39	32	1	-	28	23	1	-
Present	83	75	1.1	(1.0-1.3)	46	43	1.3	(1.0-1.9)	42	38	1.7	(1.1-2.5)
Mental Health
Good	48	68	1	-	21	30	1	-	14	20	1	-
Intermediate	55	75	1.1	(0.9-1.4)	27	39	1.3	(0.8-2.1)	23	32	1.6	(0.9-2.8)
Poor	66	74	1.1	(0.9-1.3)	37	42	1.2	(0.8-2.0)	33	37	1.7	(1.0-3.0)
Number of distressing somatic symptoms
0	88	68	1	-	41	33	1	-	31	24	1	-
1	36	72	1.1	(0.9-1.3)	17	36	1.1	(0.7-1.7)	17	34	1.3	(0.8-2.2)
≥2	45	83	1.2	(1.0-1.5)	27	50	1.5	(1.0-2.2)	22	41	1.6	(1.0-2.5)
Treatment
Nonec	77	69	1	-	35	32	1	-	32	29	1	-
Surgeryd	23	56	0.8	(0.6-1.1)	12	30	0.9	(0.5-1.5)	10	24	0.7	(0.4-1.4)
Injections or physical therapy but not surgerye	69	85	1.2	(1.0-1.4)	38	49	1.5	(1.1-2.2)	28	35	1.2	(0.8-1.8)

^aRoland Morris score > 11

^bPrevalence ratios adjusted for the other risk factors in the table, and also for sex and age (20-39, 40-49 and 50-64 years). For each regression model, analysis was restricted to patients with complete information on all relevant variables (233 for LBP in past 4 weeks, 227 for LBP on > 14 days in past 4 weeks, and 233 for disabling LBP in past 4 weeks).

^cNo back surgery after MRI investigation and no injections or physical therapy after baseline questionnaire

^dBack surgery after MRI investigation

^eInjections or physical therapy after baseline questionnaire, but no back surgery after MRI investigation