Table 2.

General linear model for repeated measures examining patients with low back pain-related disability who presented at a neck and back outpatient clinic and completed a questionnaire for the initial assessment (Time 1) and six months later (Time 2) (N = 4975). Higher scores indicate greater low back pain-related disability

Time 1			Time 2
Model	M	SD	M	SD	M diff	SE diff	p diff	F	df	df(error)	p
Mean values of low back pain-related disability
No sickness absence	24.15	11.91	21.74	13.09	-2.42	0.25	< 0.001
Graded sickness absence	29.15	11.97	24.79	13.24	-4.36	0.37	< 0.001
Full sickness absence	36.13	14.90	29.70	15.99	-6.43	0.34	< 0.001
Between subjects
Intercept								23971.63	1	4972	< 0.001
Sickness absence								309.76	2	4972	< 0.001
Within subjects
Time								558.92	1	4972	< 0.001
Time * sickness absence								46.75	2	4972	< 0.001