Table 2.

Comparison of Patient Descriptive Characteristics on Baseline and Post-Study Measures Between Electronic and Paper Groups (Including Only Those With Pre-Post Values)

	Electronic						Paper						Difference
Variable a		Pre		Post				Pre		Post			Pre	Post	Change
	n	Mean	SD	Mean	SD	Pb	n	Mean	SD	Mean	SD	Pb	Pc	Pd	Pe
Brief Pain Inventory (BPI) Interferencea	54	6.2	2.2	5.9	2.1	0.457	44	6.5	2.1	6.3	2.1	0.637	0.492	0.377	0.860
Pain Catastrophizing Scale (PCS)	54	1.9	0.8	1.7	0.9	0.030	44	1.9	1.0	1.8	1.0	0.358	0.932	0.529	0.413
Helplessness	54	1.9	0.9	1.6	0.9	0.047	44	1.9	1.1	1.8	1.0	0.436	0.806	0.309	0.399
Magnification	54	1.5	0.9	1.3	1.0	0.134	44	1.5	1.1	1.4	1.1	0.442	0.983	0.706	0.646
Rumination	54	2.3	1.0	2.0	1.1	0.066	44	2.1	1.1	2.0	1.1	0.410	0.578	0.879	0.490
Oswestry Disability Index (ODI)	54	3.2	0.8	3.2	0.9	0.802	44	3.5	0.8	3.4	0.8	0.643	0.170	0.226	0.920
CES-D Depression	54	2.5	0.6	2.3	0.6	0.003	44	2.5	0.5	2.4	0.7	0.489	0.673	0.508	0.198

SD = standard deviation; CES-D = Center for Epidemiologic Studies-Depression Scale.

^aThese are average scores. To obtain total scores, multiply by 7 for the BPI Interference, by 13 for the PCS, by 6 for Helplessness, by 3 for Magnification, by 4 for Rumination, by 10 for the CES-D Depression Scale. For the ODI, percent disability is (x-1)*20 where x is the average score.

^bP-value from paired t-test that the pre-post difference is zero.

^cP-value from two sample t-test that electronic and paper means are the same at pre-test.

^dP-value from two sample t-test that electronic and paper means are the same at post-test.

^eP-value from two sample t-test that the pre-post electronic and paper means are the same.