Discrepancies between modified Medical Research Council dyspnea score and COPD assessment test score in patients with COPD

Figures & data

Table 1 Baseline characteristics of patients (n=790)

Characteristics	Mean ± SD or n (%)
Age (years)	71.1±7.8
Male	720 (90.8)
Smoking
Current	220 (27.8)
Ex	540 (68.4)
Never	30 (3.8)
pBD FVC (L)	3.0±0.8
pBD FVC (%)	81.7±17.6
pBD FEV1 (L)	1.5±0.5
pBD FEV1 (%)	55.7±16.7
GOLD stage 1	39 (4.9)
GOLD stage 2	443 (56.1)
GOLD stage 3	259 (32.8)
GOLD stage 4	49 (6.2)
pBD FEV1/FVC (%)	49.0±12.0
CAT	15.6±7.8
mMRC	1.6±1.0
SGRQ-C	35.0±19.7

Abbreviations: SD, standard deviation; pBD, post-bronchodilator; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; CAT, COPD assessment test; mMRC, modified Medical Research Council; SGRQ-C, St George’s Respiratory Questionnaire for COPD patients.

Figure 1 Correlation between CAT and other scores.

Notes: (A) Correlation between CAT and mMRC scores. Although there was a significant correlation between the CAT and mMRC scores, the correlation was not strong. (B) Correlation between CAT and SGRQ-C scores. The CAT score was well correlated with the SGRQ-C score.

Abbreviations: CAT, COPD assessment test; mMRC, modified Medical Research Council; SGRQ-C, St George’s Respiratory Questionnaire for COPD patients.

Figure 2 Histogram of CAT scores according to mMRC score.

Note: There was a wide variation in the CAT scores in each mMRC group.
Abbreviations: CAT, COPD assessment test; mMRC, modified Medical Research Council.

Figure 3 ROC curve of CAT score.

Notes: ROC curve for (A) an mMRC score of 2 and (B) an mMRC score of 1. A CAT score of 15 was compatible with an mMRC score of 2, and a CAT score of 10 was compatible with an mMRC score of 1.
Abbreviations: ROC, receiver operating characteristic; CAT, COPD assessment test; mMRC, modified Medical Research Council; AUC, area under the ROC curve; CI, confidence interval.

Figure 4 Classification of patients with COPD according to four cutoff points.

Notes: A, less symptomatic and low-risk group. B, more symptomatic and low-risk group. C, less symptomatic and high-risk group. D, more symptomatic and high-risk group.
Abbreviations: κ, coefficient of agreement; CAT, COPD assessment test; mMRC, modified Medical Research Council.

Figure 5 Discrepancy between a CAT score of 10 and an mMRC score of 1.

Notes: A, less symptomatic and low-risk group. B, more symptomatic and low-risk group. C, less symptomatic and high-risk group. D, more symptomatic and high-risk group.
Abbreviations: CAT, COPD assessment test; mMRC, modified Medical Research Council.

Figure 6 Discrepancy between a CAT score of 15 and an mMRC score of 2.

Notes: A, less symptomatic and low-risk group. B, more symptomatic and low-risk group. C, less symptomatic and high-risk group. D, more symptomatic and high-risk group.
Abbreviations: CAT, COPD assessment test; mMRC, modified Medical Research Council.