Measuring anxiety after spinal cord injury: Development and psychometric characteristics of the SCI-QOL Anxiety item bank and linkage with GAD-7

Figures & data

Table 1. Demographic and Injury Characteristics of Calibration Sample and GAD Crosswalk Subsample

Variable	Calibration Sample (n = 716) Mean (SD), n (%)	GAD Crosswalk Subsample (n = 465) Mean (SD), n (%)
Age (years)	43.0 (15.3)	41.8 (15.6)
Sex
Male	558 (78%)	363 (78%)
Female	158 (22%)	102 (22%)
Ethnicity
Hispanic	81 (11%)	57 (12%)
Non-Hispanic	631 (88%)	405 (87%)
Not provided (refused)	4 (1%)	3 (1%)
Race
Caucasian	505 (70%)	319 (69%)
African-American	125 (17%)	90 (19%)
Asian	8 (1%)	5 (1%)
More than one race	9 (1%)	8 (2%)
Other	56 (8%)	39 (8%)
Not Provided (refused)	13 (1%)	4 (1%)
Time Since Injury	7.1 (10.0)	6.56 (9.5)
<1 year post injury	195 (27%)	161 (35%)
1–3 years post injury	186 (26%)	118 (25%)
>3 years post injury	335 (47%)	186 (40%)
Diagnosis
Paraplegia Complete	182 (25%)	128 (27%)
Paraplegia Incomplete	143 (20%)	90 (19%)
Tetraplegia Complete	157 (22%)	98 (22%)
Tetraplegia Incomplete	230 (32%)	147 (32%)
Unknown/Missing	4 (1%)	2 (0%)

Figure 1. SCI-QOL Anxiety Item Bank Test Information and Precision.

Table 2. SCI-QOL Anxiety Descriptive Item Statistics

Item ID	Item Stem	Mean	SD	% at Min	% at Max
Anxiety_29	I felt trapped in my own body.	2.04	1.262	50.3	6.6
Anxiety_30	I was afraid that I would be unable to live alone.	2.14	1.365	50.1	8.7
EDANX05^PN	I felt anxious.	2.20	1.134	35.5	4.3
EDANX07^PN	I felt like I needed help for my anxiety.	1.65	1.017	64.9	2.0
EDANX18^PN	I had sudden feelings of panic.	1.44	0.774	70.7	0.3
EDANX20^PN	I was easily startled.	1.70	0.969	57.0	2.1
EDANX26^PN	I felt fidgety.	1.80	1.033	54.9	2.0
EDANX27^PN	I felt something awful would happen.	1.63	0.925	60.8	1.4
EDANX30^PN	I felt worried.	2.22	1.125	35.6	3.6
EDANX33^P	I felt terrified.	1.36	0.720	75.8	0.4
EDANX41^PN	My worries overwhelmed me.	1.81	1.046	53.2	2.8
EDANX46^PN	I felt nervous.	2.08	1.058	39.4	2.5
EDANX48^PN	Many situations made me worry.	2.00	1.034	41.1	2.1
EDANX51^PN	I had trouble relaxing.	2.29	1.147	33.0	4.6
EDANX53^PN	I felt uneasy.	2.25	1.073	31.0	2.9
EDANX54^PN	I felt tense.	2.21	1.120	35.5	3.9
EDANX55^PN	I had difficulty calming down.	1.56	0.835	63.4	0.7
NQANX01	I was afraid of what the future holds for me.	2.24	1.216	39.1	5.3
NQANX02^N	I felt fearful about my future.	2.26	1.223	38.3	5.3
NQANX04^N	I worried about my physical health.	2.66	1.198	22.5	8.4
NQANX07^N	I felt nervous when my normal routine was disturbed.	1.85	1.019	50.6	1.8
NQANX17^N	I suddenly felt scared for no reason.	1.44	0.797	71.4	0.7
NQANX18^N	I worried about dying.	1.53	.900	68.4	1.3
NQANX19	I was preoccupied with my worries.	1.90	1.033	48.0	1.5
NQANX21	I felt shy.	1.81	0.978	51.4	1.3

^P = PROMIS Item.

^N = Neuro-QOL Item.

*Context for all items was “In the past 7 days…”.

Response set was 1 = Never/2 = Rarely/3 = Sometimes/4 = Often/5 = Always.

Bold text indicates items selected for the short form 9a.

Table 3. SCI-QOL Anxiety Item Response Theory Parameters

Item ID	Item Stem	Slope	Threshold 1	Threshold 2	Threshold 3	Threshold 4
Anxiety_29	I felt trapped in my own body.	2.37392	0.13701	0.62937	1.34345	1.83460
Anxiety_30	I was afraid that I would be unable to live alone.	1.49296	0.12077	0.63359	1.32981	2.07949
EDANX05^PN	I felt anxious.	1.81193	–0.34267	0.51219	1.64793	2.36671
EDANX07^PN	I felt like I needed help for my anxiety.	2.70783	0.59202	1.03829	1.83553	2.43617
EDANX18^PN	I had sudden feelings of panic.	2.60364	0.71047	1.32843	2.36893	3.26777
EDANX20^PN	I was easily startled.	1.61209	0.36316	1.26653	2.41243	3.01943
EDANX26^PN	I felt fidgety.	1.88602	0.29583	0.94761	2.01937	2.80279
EDANX27^PN	I felt something awful would happen.	2.35316	0.44202	1.13056	2.08041	2.66604
EDANX30^PN	I felt worried.	2.56032	–0.28697	0.34381	1.42237	2.09406
EDANX33^P	I felt terrified.	2.95125	0.86035	1.47563	2.32914	2.91439
EDANX41^PN	My worries overwhelmed me.	2.69690	0.22562	0.91617	1.68177	2.17792
EDANX46^PN	I felt nervous.	2.22289	–0.19025	0.52329	1.75076	2.43653
EDANX48^PN	Many situations made me worry.	2.74798	–0.10969	0.65910	1.61207	2.30627
EDANX51^PN	I had trouble relaxing.	2.06440	–0.40607	0.32092	1.46910	2.18751
EDANX53^PN	I felt uneasy.	2.27135	–0.47566	0.37749	1.50217	2.33102
EDANX54^PN	I felt tense.	2.85412	–0.27240	0.37070	1.42042	1.99433
EDANX55^PN	I had difficulty calming down.	2.45540	0.51431	1.20262	2.44249	2.95323
NQANX01	I was afraid of what the future holds for me.	2.23295	–0.20808	0.34944	1.31941	2.00312
NQANX02^N	I felt fearful about my future.	2.14504	–0.23369	0.34516	1.26921	2.03656
NQANX04^N	I worried about my physical health.	1.69017	–0.91042	–0.15415	1.22606	2.00613
NQANX07^N	I felt nervous when my normal routine was disturbed.	2.04392	0.18734	0.90650	2.02917	2.84207
NQANX17^N	I suddenly felt scared for no reason.	2.72940	0.73278	1.36019	2.22805	2.82722
NQANX18^N	I worried about dying.	1.64426	0.75077	1.47694	2.43390	3.30694
NQANX19	I was preoccupied with my worries.	2.82364	0.08204	0.70816	1.63240	2.44944
NQANX21	I felt shy.	1.58216	0.16933	1.02938	2.36013	3.38166

^P = PROMIS Item.

^N = Neuro-QOL Item.

*Context for all items was “In the past 7 days…”.

Response set was 1 = Never/2 = Rarely/3 = Sometimes/4 = Often/5 = Always.

Bold text indicates items selected for the short form 9a.

Figure 2. SCI-QOL Anxiety: Measurement Reliability by T-score and Assessment Method.

Table 4. T-score lookup table for SCI-QOL Anxiety Short Form 9a

Raw Score	Scaled (T) Score	Standard Error
9	36.3	5.7
10	41.7	4.1
11	44.1	3.8
12	46.2	3.3
13	47.9	3.1
14	49.4	2.9
15	50.7	2.8
16	51.9	2.7
17	53.0	2.6
18	54.0	2.6
19	55.1	2.6
20	56.0	2.5
21	57.0	2.5
22	57.9	2.5
23	58.9	2.5
24	59.8	2.5
25	60.7	2.5
26	61.6	2.5
27	62.5	2.5
28	63.4	2.5
29	64.3	2.5
30	65.2	2.5
31	66.1	2.5
32	67.0	2.5
33	68.0	2.5
34	68.9	2.5
35	69.8	2.5
36	70.8	2.5
37	71.8	2.5
38	72.8	2.6
39	73.9	2.6
40	75.1	2.7
41	76.4	2.8
42	77.8	2.9
43	79.4	3.1
44	81.3	3.4
45	84.2	3.9

Table 5. Breadth of Coverage for SCI-QOL Anxiety and GAD-7

Measure/Mode		# Items Admin			Score
		Mean(SD)	Min	Max	Mean(SD)	Range	% Floor	% Ceiling	SE	Reliability
SCI-QOL Anxiety	Full Bank	25(0)	25	25	50.7(9.1)	31.70–80.50	2.8%	0.1%	0.220	0.948
	9-Item fixed length CAT	9(0)	9	9	50.8(9.0)	33.14–82.23	7.5%	0.1%	0.285	0.921
	Variable-Length CAT (min 4/max 12)	7.2(2.8)	4	12	50.7(9.0)	32.47–82.14	6.8%	0.1%	0.315	0.908
	Variable-Length CAT (min 8/max 12)	8.9(1.6)	8	12	50.8(9.0)	32.47–82.14	6.8%	0.1%	0.286	0.921
	Short Form	9(0)	9	9	50.8(8.6)	36.30–77.50	6.4%	0.1%	0.326	0.899
GAD-7*		7(0)	7	7	3.86(4.34)	0–21	24.9%	0.9%	0.416	0.853

*GAD-7 raw scores; item responses scored 0–3.

Figure 3. Relationship between SCI-QOL Anxiety and GAD-7 scores. *Individuals reporting no anxiety symptoms (i.e. “never” to all items), and an extremely high amount have been omitted from this graph due to instability of score estimates.

Figure 4. Marginal Reliability of GAD-7, SCI-QOL Anxiety, and Combined (n = 465). Colors relate to the online version of the figure.

Figure 5. Scale information provided by the GAD-7, SCI-QOL Anxiety, and Combined. Colors relate to the online version of the figure.

Table 6. Linking Table: SCI-QOL Anxiety and GAD-7

GAD-7 Raw Score	SCI-QOL T-Score	SE
7	10	9.98
8	40	5.78
9	44	3.9
10	46	2.9
11	48	2.27
12	49	1.86
13	51	1.56
14	52	1.34
15	53	1.17
16	54	1.04
17	56	0.93
18	57	0.85
19	58	0.77
20	59	0.71
21	60	0.66
22	62	0.62
23	63	0.58
24	65	0.55
25	67	0.52
26	69	0.49
27	73	0.47
28	101	0.45

Note: GAD-7 items are scored 1–4 instead of 0–3.