Table 2.

Descriptive data of patients with recurrent or persistent low back pain from a randomized clinical trial investigating the outcomes of chiropractic maintenance care

Variable a		Group	All n = 319 (MC, n = 161; Control, n = 158)	Survival analysis, n = 250 (MC, n = 127; Control, n = 123)	Trajectory analysis, n = 254 (MC, n = 145; Control, n = 109)
Age at study start, mean (SD)		MC	43.4 (11.2)	43.0 (11.3)	43.5 (11.3)
		Control	43.1 (13.2)	42.4 (13.3)	42.6 (13.6)
Female, % (n)		MC	63.5 (94)	64.7 (77)	37.9 (50)
		Control	60.3 (85)	57.5 (65)	37.0 (37)
Pain intensity, 0–10, mean (SD)	1st visit	MC	5.4 (2.1)	5.2 (2.1)	5.4 (2.0)
		Control	5.4 (2.1)	5.3 (2.1)	5.6 (2.1)
	4th visit	MC	2.4 (1.8)	2.3 (1.8)	2.6 (1.8)
		Control	2.3 (1.7)	2.2 (1.7)	2.3 (1.8)
	Study start	MC	2.1 (1.5)	1.8 (1.4)	2.1 (1.5)
		Control	2.2 (1.8)	2.0 (1.6)	2.2 (1.7)
EQ5D score baseline, mean (SD)		MC	0.68 (0.23)	0.67 (0.24)	0.69 (0.21)
		Control	0.70 (0.20)	0.71 (0.20)	0.71 (0.19)
MPI Subgroup, % (n)	AC	MC	29.8 (48)	31.0 (40)	32.0 (46)
		Control	28.3 (45)	32.5 (40)	23.9 (26)
	ID	MC	20.5 (33)	21.3 (27)	20.0 (29)
		Control	18.2 (29)	18.7 (23)	22.0 (24)
	DYS	MC	30.4 (49)	29.1 (37)	32.0 (46)
		Control	30.2 (48)	29.3 (36)	34.9 (38)
	Missing	MC	19.3 (31)	18.0 (23)	24 (17)
		Control	23.3 (37)	19.5 (24)	21 (19)
RMDQ Score (study start), mean (SD)		MC	4.9 (4.0)	4.4 (3.9)	4.9 (4.1)
		Control	4.7 (4.1)	4.3 (4.1)	4.9 (3.8)

^a, No imputation has been made for missing data, mean values and percentages are based on true responses for each variable; MC Maintenance Care; SD Standard deviation; n number of participants; MPI West Haven-Yale Multidimensional Pain Inventory; AC Adaptive Coper; ID Interpersonally Distressed; DYS Dysfunctional; RMDQ Roland Morris Disability Questionnaire