Reliability and validity of the Athens Insomnia Scale in chronic pain patients

Figures & data

Table 1 Demographic characteristics of the participants

Demographic characteristics	Frequency (n)	%
Number of participants	144
Age (years)	53.3±16.2
Number of female	86	60.0
Pain durations (months)	53.6±66.7
Pain sitea
Head	37	25.7
Cervical	40	27.8
Upper shoulder and upper limbs	80	55.6
Thoracic	24	16.7
Abdominal	22	15.3
Lower back	74	51.4
Lower limbs	98	68.1
Genital	6	4.2
>3 major sites	65	45.0
Classification of chronic pain according to new IASP classificationa
Code 1: chronic primary pain	89	61.8
Code 2: chronic cancer pain	0	0.0
Code 3: chronic postsurgical and posttraumatic pain	30	20.8
Code 4: chronic neuropathic pain	15	10.4
Code 5: chronic headache and orofacial pain	4	2.8
Code 6: chronic visceral pain	0	0.0
Code 7: chronic musculoskeletal pain	6	4.2
Received at least high school education	128	88.9
Marital status
Married	76	52.8
Single	36	25.0
Divorced	18	12.5
Remarried	6	4.1
Widowed	8	5.6
Work status
Working full time	41	28.5
Working part time	7	4.9
Not employed	52	36.1
Retired due to pain	10	6.9
Homemakers	30	20.8
Other	4	2.8
Taking sleep pills	72	50.0
Insomnia symptoms	131	91.0
Difficulty in initiating sleep	69	47.9
Difficulty in maintaining sleep	109	75.7
Early morning awakening	26	18.1

Note:

a Duplicate reports of pain site are included.

Abbreviation: IASP, International Association for the Study of Pain.

Table 2 Mean, SD, and ranges of scores of psychological measures

Measure	All patients (N=144)		Patients with insomnia (N=131)		Patients without insomnia (N=13)
	Mean±SD	Range	Mean±SD	Range	Mean±SD	Range
AIS-8 (0–24)	10.8±5.7	0–24	11.4±5.6	0–24	5.2±3.4	0–11
AIS-5-nocturnal sleep problem (0–15)	6.7±4.1	0–15	7.1±4.1	0–15	2.7±2.5	0–7
AIS-daytime dysfunction (0–9)	4.1±2.3	0–9	4.3±2.2	0–9	2.5±1.9	0–6
NRS (0–10)	6.0±2.0	0.3–10.0	6.2±1.9	1.8–10.0	4.4±2.5	0.3–7.8
PDAS (0–60)	28.9±14.8	0–60	29.7±15.0	0–60	20.5±10.3	5–34
HADS-total (0–42)	19.8±9.2	1–42	20.4±9.3	1–42	13.1±5.3	5–23
HADS-anxiety (0–21)	9.3±4.8	0–21	9.6±4.8	0–21	6.2±3.0	1–10
HADS-depression (0–21)	10.4±5.2	1–21	10.8±5.3	1–21	6.8±2.9	3–13
PCS-total (0–52)	38.1±10.0	11–52	38.8±9.7	11–52	31.1±10.9	13–46
PCS-rumination (0–20)	17.0±3.5	0–20	17.1±3.6	0–20	16.2±3.2	11–20
PCS-magnification (0–12)	7.3±3.2	0–12	7.6±3.1	0–12	4.8±2.8	1–9
PCS-helplessness (0–20)	13.7±4.6	0–20	14.1±4.3	1–20	10.1±5.9	0–18
PSEQ (0–60)	20.1±14.1	0–60	19.9±14.4	0–60	23.0±11.3	0–42

Abbreviations: AIS, Athens Insomnia Scale; HADS, hospital anxiety and depression scale; NRS, numerical rating scale; PCS, pain catastrophizing scale; PDAS, pain disability assessment scale; PSEQ, pain self-efficacy questionnaire.

Figure 1 A 2-factor model of AIS-8.

Abbreviation: AIS, Athens Insomnia Scale.

Figure 2 A one-factor model of AIS-5.

Abbreviation: AIS, Athens Insomnia Scale.

Table 3 Correlation coefficients between AIS and the other psychological measures

Measure	AIS-8 (95% CI)	AIS-5 (95% CI)
NRS	0.36 (0.21 to 0.50)	0.35 (0.19 to 0.48)
PDAS	0.46 (0.33 to 0.58)	0.37 (0.22 to 0.51)
HADS-anxiety	0.54 (0.41 to 0.65)	0.42 (0.28 to 0.55)
HADS-depression	0.64 (0.53 to 0.73)	0.52 (0.39 to 0.63)
PCS-total	0.36 (0.21 to 0.49)	0.26 (0.10 to 0.41)
PCS-rumination	0.23 (0.07 to 0.38)	0.17 (0.01 to 0.33)
PCS-magnification	0.37 (0.22 to 0.50)	0.27 (0.11 to 0.42)
PCS-helplessness	0.35 (0.19 to 0.48)	0.24 (0.08 to 0.39)
PSEQ	−0.47 (−0.59 to −0.33)	−0.35 (−0.48 to −0.19)

Abbreviations: AIS, Athens Insomnia Scale; HADS, hospital anxiety and depression scale; NRS, numerical rating scale; PCS, pain catastrophizing scale; PDAS, pain disability assessment scale; PSEQ, pain self-efficacy questionnaire.

Figure 3 ROC curve of the AIS-8 and AIS-5.

Notes: (A) ROC curve of the AIS-8. (B) ROC curve of the AIS-5.
Abbreviations: AIS, Athens Insomnia Scale; ROC, receiver-operating characteristic.

Table 4 Sensitivity and specificity values of the AIS

Measure	Cut-off score	Sensitivity (%)	Specificity (%)	AUC (95% CI)
AIS-8	7	75	69	0.82 (0.72 to 0.91)
	8a	72a	85a
	9	66	85
AIS-5	3	83	46	0.82 (0.71 to 0.92)
	4a	78a	70a
	5	69	76

Note:

a Optimal cutoff score values are shown in bold.

Abbreviations: AIS, Athens Insomnia Scale; AUC, area under the curve.