Detection of acute deterioration in health status visit among COPD patients by monitoring COPD assessment test score

Figures & data

Table 1 Demographic and clinical characteristics of COPD patients

Characteristics	N=140
Number of follow-up visits (n)	354
Number of visits/case	3.6±1.5
Age, years	71.1±8.4
Male sex, n (%)	79 (56.4)
FEV1 percentage predicted	47.4±18.2
FEV1/FVC, %	51.8±10.7
SGRQ score	39.3±21.2
mMRC score	1.9±1.1
CAT score	9.9±6.4
6-MWD, m	324.0±103.4
GOLD classification, n (%)
I	10 (7.1)
II	51 (36.4)
III	51 (36.4)
IV	26 (18.6)
Missing	2 (1.5)

Note: Data are n (%) or mean ± SD.

Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, percentage predicted, percentage predicted of forced expiratory volume in first second; FEV₁/FVC, ratio of FEV₁ to forced vital capacity; SGRQ, St George’s Respiratory Questionnaire; mMRC, modified Medical Research Council score; CAT, COPD Assessment Test; 6-MWD, 6-minute walking distance; GOLD, Global initiative for chronic Obstructive Lung Disease.

Table 2 Mean CAT score difference by COPD status (stable, worsening, and exacerbation visits)

Assessment of COPD status (n=354)	CAT score, mean difference (95% confidence interval)	P-value
Patients global assessment
Stable–stable (n=286)	0.05 (−0.37–0.46)	0.817
Stable–worsening (n=68)	6.07 (4.95–7.19)	<0.0001
Physician global assessment
Stable–stable (n=298)	0.18 (−0.23–0.60)	0.389
Stable–mild exacerbation (n=37)	5.51 (4.39–6.63)	<0.0001
Stable–moderate exacerbation (n=19)	8.84 (6.29–11.39)	<0.0001
Mild–moderate exacerbation	3.22 (0.46–5.98)	0.007

Note: Data are mean difference (95% confidence interval).

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

Table 3 Discriminative property change of CAT score cut-off points for acute deterioration in health status detection

Change of CAT score cut-off points	Sensitivity, %	Specificity, %	Accuracy, %	PPV, %	NPV, %
1	96.4	54.4	61.0	28.4	98.8
2	92.9	66.8	70.9	34.4	98.0
3	87.5	75.5	77.4	40.2	97.0
4*	76.8	83.6	82.4	46.7	95.0
5	66.1	91.3	87.3	58.7	93.5
6	58.9	95.3	89.5	70.2	92.5
7	44.6	97.3	88.9	75.8	90.3
8	30.4	98.3	87.6	77.3	88.3
9	25.0	98.7	87.0	77.8	87.5
10	23.6	98.7	86.7	76.5	87.5

Note:

* The best cut-off point.

Abbreviations: CAT, COPD Assessment Test; COPD, chronic obstructive pulmonary disease; PPV, positive predictive value; NPV, negative predictive value.

Figure 1 Receiver operating curve of the CAT score for detecting exacerbation in COPD patients.

Abbreviations: AUC, area under the curve; CI, confidence interval; CAT, COPD Assessment Test; COPD, chronic obstructive pulmonary disease.