Dialectal influence on chronic pulmonary disease assessment test: the reliability and validity study

Figures & data

Table 1 Characteristics of 160 patients with COPD enrolled in the study

Variables	Thai version (N=80)	Northern Thai dialect version (N=80)	P-value
Sex (M:F) %	60.0:40.0	55.0:45.0	0.52
Age (year)	72.3±8.7	70.7±9.2	0.27
BMI (kg/m^2)	20.6±4.6	21.3±6.7	0.41
FEV1 (% predicted)	50.1±23.2	49.0±20.5	0.74
FEV1/FVC (%)	53.3±11.5	52.4±11.3	0.58
SGRQ score (0–100)	40.3±20.3	41.7±21.0	0.65
mMRC dyspnea score (0–4)	2.0±1.1	1.9±1.1	0.68
CAT score (0–40)	12.4±7.6	11.7±6.8	0.52
6-MWD (meter)	319.6±102.8	320.5±100.9	0.96
GOLD classification n (%)
I	10 (12.0)	5 (6.2)	0.64
II	26 (33.0)	31 (38.8)
III	32 (40.0)	29 (36.2)
IV	11 (13.8)	15 (18.8)
Missing	1 (1.2)	0 (0.0)
Inhaled medications n (%)
LAAC	1 (1.2)	1 (1.2)
ICS + LABA	49 (61.2)	50 (62.5)	0.98
ICS + LABA + LAAC	30 (37.5)	29 (36.2)

Note: Data were n (%) or mean ± SD.

Abbreviations: COPD, chronic obstructive pulmonary disease; BMI, body mass index; FEV₁ (% predicted), percentage predicted of forced expiratory volume in the first second; FEV₁/FVC, ratio of forced expiratory volume in the first second to force vital capacity; SGRQ, St George’s Respiratory Questionnaire; mMRC, modified Medical Research Council scale; CAT, COPD Assessment Test; 6-MWD, 6-minute walk distance; LAAC, long acting anticholinergics; ICS, inhaled corticosteroids; LABA, long acting beta2-agonists; GOLD, Global Initiative for Chronic Obstructive Lung Disease; SD, standard deviation.

Figure 1 Schematic diagram of randomization.

Abbreviations: COPD, chronic obstructive pulmonary disease; CAT, COPD Assessment Test.

Table 2 Cross-sectional validity between each domain of CAT and SGRQ at the patients’ first visit

CAT	SGRQ
	Symptom	Functional	Impact	Total
Thai version
Symptom	0.57*	0.28*	0.31*	0.38*
Functional	0.45*	0.59*	0.51*	0.60*
Impact	0.37*	0.43*	0.53*	0.53*
Total	0.54*	0.51*	0.54*	0.60*
Northern Thai dialect version
Symptom	0.55*	0.34*	0.41*	0.44*
Functional	0.44*	0.71*	0.68*	0.73*
Impact	0.42*	0.63*	0.71*	0.71*
Total	0.56*	0.69*	0.74*	0.77*

Note:

* Correlation is significant at the 0.05 level.

Abbreviations: CAT, COPD Assessment Test; SGRQ, St George’s Respiratory Questionnaire.

Figure 2 Correlation between SGRQ and CAT scores.

Notes: (A) Thai version (r=0.60, P<0.001) (B) Northern Thai dialect version (r=0.77, P<0.001).
Abbreviations: SGRQ, St George’s Respiratory Questionnaire; CAT, COPD Assessment Test.

Table 3 Correlations between each domain of CAT and concurrent measures of disease severity

CAT	Disease severity
	FEV1 (% predicted)	mMRC	6-MWD
Thai version
Symptom	0.03	0.14	−0.09
Functional	−0.16	0.58*	−0.38*
Impact	0.04	0.31*	−0.12
Total	−0.02	0.39*	−0.19
Northern Thai dialect version
Symptom	−0.09	0.07	−0.03
Functional	−0.11	0.62*	−0.46*
Impact	−0.23*	0.50*	−0.41*
Total	−0.19	0.52*	−0.39*

Note:

* Correlation is significant at the 0.05 level.

Abbreviations: CAT, COPD Assessment Test; FEV₁ (% predicted), percentage predicted of forced expiratory volume in the first second; mMRC, modified Medical Research Council scale; 6-MWD, 6-minute walk distance.

Table S1 Thai version

Table S2 Northern Thai dialect version