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

Abstract

Chin Kook Rhee,1 Jin Woo Kim,2 Yong Il Hwang,3 Jin Hwa Lee,4 Ki-Suck Jung,3 Myung Goo Lee,5 Kwang Ha Yoo,6 Sang Haak Lee,7 Kyeong-Cheol Shin,8 Hyoung Kyu Yoon9 1Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, 2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Uijeongbu St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, 3Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, 4Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, 5Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, 6Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, 7Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, St Paul’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, 8Regional Center for Respiratory Disease, Yeungnam University Medical Center, Yeungnam University College of Medicine, Daegu, 9Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yeouido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea Background and objective: According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, either a modified Medical Research Council (mMRC) dyspnea score of ≥2 or a chronic obstructive pulmonary disease (COPD) assessment test (CAT) score of ≥10 is considered to represent COPD patients who are more symptomatic. We aimed to identify the ideal CAT score that exhibits minimal discrepancy with the mMRC score.Methods: A receiver operating characteristic curve of the CAT score was generated for an mMRC scores of 1 and 2. A concordance analysis was applied to quantify the association between the frequencies of patients categorized into GOLD groups A–D using symptom cutoff points. A κ-coefficient was calculated.Results: For an mMRC score of 2, a CAT score of 15 showed the maximum value of Youden’s index with a sensitivity and specificity of 0.70 and 0.66, respectively (area under the receiver operating characteristic curve [AUC] 0.74; 95% confidence interval [CI], 0.70–0.77). For an mMRC score of 1, a CAT score of 10 showed the maximum value of Youden’s index with a sensitivity and specificity of 0.77 and 0.65, respectively (AUC 0.77; 95% CI, 0.72–0.83). The κ value for concordance was highest between an mMRC score of 1 and a CAT score of 10 (0.66), followed by an mMRC score of 2 and a CAT score of 15 (0.56), an mMRC score of 2 and a CAT score of 10 (0.47), and an mMRC score of 1 and a CAT score of 15 (0.43).Conclusion: A CAT score of 10 was most concordant with an mMRC score of 1 when classifying patients with COPD into GOLD groups A–D. However, a discrepancy remains between the CAT and mMRC scoring systems. Keywords: COPD, CAT, mMRC, concordance, discrepancy