Psychometric properties of the Korean version of the Pulmonary Rehabilitation Adapted Index of Self-Efficacy (PRAISE) for individuals with COPD

Figures & data

Table 1 Participant characteristics N=118

Variable	Category	n (%)	Mean ± SD
General characteristics	Age (years)		69.41±9.23
	<65	34 (28.8)
	65–75	48 (40.7)
	>75	36 (30.5)
	Sex
	Male	103 (87.3)
	Female	15 (12.7)
	Education
	≤ Middle school	67 (56.8)
	≤ High school	34 (28.8)
	≥ College	17 (14.4)
	Marital status
	Married	115 (97.4)
	Single	3 (2.6)
	Economic status
	Low	3 (2.6)
	Middle	70 (59.3)
	High	45 (38.1)
	Occupation
	None	66 (55.9)
	Self-employed	44 (37.3)
	Office worker	8 (6.8)
Disease-related characteristics	Duration of disease (years)		10.05±9.07
	<10	77 (65.3)
	11–19.9	20 (16.9)
	≥20	21 (17.8)
	Cardiovascular comorbidities
	Hypertension	15 (12.7)
	Heart problems	18 (15.3)
	None	85 (72.0)
	Smoking
	Never	22 (18.7)
	Ex-smoker	83 (70.3)
	Current smoker	13 (11.0)
	mMRC dyspnea
	0	11 (9.3)
	1	49 (41.5)
	2	24 (20.4)
	3	17 (14.4)
	4	17 (14.4)
	Body mass index (kg/m^2)		22.87±3.72
	<19	13 (11.0)
	19–22.9	51 (43.2)
	23–24.9	28 (23.7)
	≥25	26 (22.1)
	Airflow obstruction
	FEV1		63.51±24.01
	FEV1/FVC		54.47±19.61
	GOLD stage
	I	32 (27.1)
	II	49 (41.5)
	III	27 (22.9)
	IV	10 (8.5)

Abbreviations: FEV, forced expiratory volume; FVC, forced vital capacity; GOLD, Global initiative for chronic Obstructive Lung Disease; mMRC, modified Medical Research Council.

Table 2 Reliability and factor loadings for the PRAISE

Item	I-CVI	Mean ± SD	Alpha if item deleted	Corrected item to total correlation	Communalities		Factor
					Initial	Extraction	1	2
Total		2.88±0.43
2	1.0	2.89±0.58	0.93	0.55	0.43	0.34	0.57
3	1.0	2.93±0.55	0.92	0.74	0.61	0.57	0.70
5	1.0	2.92±0.56	0.92	0.86	0.77	0.79	0.85
6	1.0	2.91±0.57	0.93	0.74	0.65	0.64	0.90
8	1.0	2.96±0.51	0.92	0.78	0.73	0.70	0.60
9	0.8	2.80±0.63	0.93	0.49	0.32	0.26	0.46
10	1.0	2.95±0.50	0.92	0.78	0.65	0.65	0.74
11	1.0	2.92±0.52	0.92	0.85	0.78	0.80	0.90
13	1.0	2.98±0.47	0.92	0.83	0.76	0.75	0.94
14	1.0	2.93±0.55	0.92	0.81	0.73	0.71	0.81
15	0.8	2.87±0.56	0.93	0.67	0.54	0.51	0.60
4	1.0	2.64±0.69	0.78	0.57	0.45	0.44		0.58
7	1.0	2.82±0.76	0.65	0.70	0.58	0.76		0.91
12	0.8	2.80±0.71	0.71	0.64	0.54	0.52		0.66
Scale CVI	0.96
Eigenvalue							7.33	4.62
Percentage of variance explained by each factor							53.8	6.5
Percentage of variance explained by factors							60.3
Cronbach’s α coefficient							0.94	0.79
Cronbach’s α coefficient (Total)							0.93

Abbreviations: I-CVI, item content validity index; PRAISE, pulmonary rehabilitation adapted index of self-efficacy.

Table 3 Correlations between the PRAISE factors

	Factor 1	Factor 2
Factor 1	1
Factor 2	0.62**	1
PRAISE total score	0.97**	0.78**

Note:

** Correlation is significant at the 0.01 level.

Abbreviation: PRAISE, pulmonary rehabilitation adapted index of self-efficacy.

Table 4 Correlations between the PRAISE, 6-MWD, and SGRQ scores

Variable	6-MWD	SGRQ
		Total	Symptom	Activity	Impact
Total SE
r	0.214*	−0.345**	−0.321**	−0.300**	−0.314**
p	0.039	0.000	0.000	0.001	0.001
General SE
r	0.157	−0.302**	−0.329**	−0.228*	−0.285**
p	0.132	0.001	0.000	0.013	0.002
Exercise SE
r	0.308**	−0.353**	−0.205*	−0.399**	−0.295**
p	0.003	0.000	0.026	0.000	0.001

Notes:

* Correlation is significant at the 0.05 level.

** Correlation is significant at the 0.01 level.

Abbreviations: PRAISE, pulmonary rehabilitation adapted index of self-efficacy; 6-MWD, 6-minute walking distance; SE, self-efficacy; SGRQ, Saint George Respiratory Questionnaire.