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ORIGINAL ARTICLE
New scoring system for the differentiation of chronic obstructive pulmonary disease and asthma YOUNG SEOK LEE,1,2 SEUNGHEE BAEK,3 YOUSANG KO,1 MI-YEONG KIM,1 HYUN-KYUNG LEE,1 TAE-BUM KIM,4 YOU SOOK CHO,4 HEE-BOM MOON,4 SANG-DO LEE5 AND YEON-MOK OH5 1
Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, 2Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, 3Department of Clinical Epidemiology and Biostatistics, Ulsan College of Medicine, Asan Medical Center, and Departments of 4Allergy and Clinical Immunology and 5Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
ABSTRACT Background and objective: It remains difficult to differentiate between chronic obstructive pulmonary disease (COPD) and asthma in clinical practice, especially in a primary care setting. The purpose of this study was to develop a new scoring system for differentiating between COPD and asthma, and to evaluate its effectiveness. Methods: First, to identify important variables differentiating COPD from asthma, the data of 197 patients with COPD and 138 patients with asthma were assessed retrospectively. Secondly, a scoring system that was based on these variables was then developed, and its performance was internally validated using a bootstrapping-based method. Thirdly, the scoring system was externally validated using prospectively collected data from patients with COPD (n = 104) or asthma (n = 96). Results: The final scoring system was composed of the four variables: age of onset of breathlessness (60 years, 4 points), continuous breathlessness (no, 0 points; yes, 1 point), diurnal variation of breathlessness (yes, 0 points; no, 1 point) and emphysematous change in chest X-ray (no, 0 points; yes, 1 point). The patients were classified by their total score into three categories: 0–2 points, probable asthma; 3–4 points, difficult-todifferentiate; 5–7 points, probable COPD. The new scoring system performed well in the external validation dataset (area under the curve, 0.86; 95% confidence interval: 0.813–0.911; P < 0.001). Conclusions: The new scoring system that was developed in this study may be a useful tool for differentiating between COPD and asthma in primary care.
Correspondence: Yeon-Mok Oh, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan, College of Medicine, Asanbyungwon-gil, Songpa-gu, Seoul, 138-736, South Korea. Email: [email protected] Received 14 September 2014; invited to revise 3 November 2014; revised 22 December 2014; accepted 18 January 2015 (Associate Editor: Shu Hashimoto). Article first published online: 30 March 2015 © 2015 Asian Pacific Society of Respirology
SUMMARY AT A GLANCE Despite efforts to differentiate between COPD and asthma, misdiagnosis is still a serious problem in general practice, especially in a primary care setting. This study suggests a new scoring system that may be a useful tool for differentiating between COPD and asthma in primary care.
Key words: asthma, chronic obstructive pulmonary disease, differential diagnosis, primary care physician. Abbreviation: ACOS, asthma–chronic obstructive pulmonary disease overlap syndrome; AUC, area under the receiver operating characteristic curve; CI, confidence interval; COPD, chronic obstructive pulmonary disease; CT, computed tomography; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PFT, pulmonary function test.
INTRODUCTION Chronic obstructive pulmonary disease (COPD) and asthma are leading causes of morbidity and mortality worldwide and associate with significant economic/ social burdens.1,2 COPD is usually characterized by progressive and irreversible airflow limitation, while asthma is characterized by airway hyperresponsiveness and reversible airflow limitation. In addition, the basis for COPD treatment is inhaled bronchodilator, except in patients at risk of recurrent exacerbations, while inhaled corticosteroid is used in asthma.1,2 Despite these differences between the two diseases, misdiagnosis is still a serious problem in general practice.1–5 Primary physicians often misdiagnose the two diseases because of a lack of proper diagnostic tools and difficulties in interpreting the spirometry data.6–9 Patients could be receiving incorrect therapy if they are misdiagnosed in primary care; as a result, they may experience a poor response to therapy and have a high risk of adverse events.9–11 For this reason, Respirology (2015) 20, 626–632 doi: 10.1111/resp.12511
New scoring system in COPD and asthma
many symptom-based questionnaires for differentiating COPD and asthma were developed.12–19 However, many of these questionnaires are very complex (e.g. they include many items), and the results cannot suggest an action plan. The aim of this study was to develop a scoring system that can be used as a tool to differentiate between COPD and asthma in primary care, and to evaluate its effectiveness. This scoring system may be useful for guiding primary physicians in the identification, treatment and follow-up care of COPD and asthma.
627 tor test). A reversible component was defined as a change of more than 400 mL, and achievement of at least 80% of the predicted FEV1 after bronchodilator or other treatments (including oral or inhaled high dose steroid), as assessed by follow-up PFT or bronchodilator test.4,24,25 Asthma was considered to be present in any patient who fulfilled one or more of the following criteria: (i) variability in the maximum diurnal peak expiratory flow (>20%) over the course of 14 days; (ii) the presence of a post-bronchodilator FEV1/FVC ≥0.70 or post-bronchodilator FEV1/FVC
ORIGINAL ARTICLE
New scoring system for the differentiation of chronic obstructive pulmonary disease and asthma YOUNG SEOK LEE,1,2 SEUNGHEE BAEK,3 YOUSANG KO,1 MI-YEONG KIM,1 HYUN-KYUNG LEE,1 TAE-BUM KIM,4 YOU SOOK CHO,4 HEE-BOM MOON,4 SANG-DO LEE5 AND YEON-MOK OH5 1
Division of Pulmonary Allergy and Critical Care Medicine, Department of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, 2Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, 3Department of Clinical Epidemiology and Biostatistics, Ulsan College of Medicine, Asan Medical Center, and Departments of 4Allergy and Clinical Immunology and 5Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
ABSTRACT Background and objective: It remains difficult to differentiate between chronic obstructive pulmonary disease (COPD) and asthma in clinical practice, especially in a primary care setting. The purpose of this study was to develop a new scoring system for differentiating between COPD and asthma, and to evaluate its effectiveness. Methods: First, to identify important variables differentiating COPD from asthma, the data of 197 patients with COPD and 138 patients with asthma were assessed retrospectively. Secondly, a scoring system that was based on these variables was then developed, and its performance was internally validated using a bootstrapping-based method. Thirdly, the scoring system was externally validated using prospectively collected data from patients with COPD (n = 104) or asthma (n = 96). Results: The final scoring system was composed of the four variables: age of onset of breathlessness (60 years, 4 points), continuous breathlessness (no, 0 points; yes, 1 point), diurnal variation of breathlessness (yes, 0 points; no, 1 point) and emphysematous change in chest X-ray (no, 0 points; yes, 1 point). The patients were classified by their total score into three categories: 0–2 points, probable asthma; 3–4 points, difficult-todifferentiate; 5–7 points, probable COPD. The new scoring system performed well in the external validation dataset (area under the curve, 0.86; 95% confidence interval: 0.813–0.911; P < 0.001). Conclusions: The new scoring system that was developed in this study may be a useful tool for differentiating between COPD and asthma in primary care.
Correspondence: Yeon-Mok Oh, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan, College of Medicine, Asanbyungwon-gil, Songpa-gu, Seoul, 138-736, South Korea. Email: [email protected] Received 14 September 2014; invited to revise 3 November 2014; revised 22 December 2014; accepted 18 January 2015 (Associate Editor: Shu Hashimoto). Article first published online: 30 March 2015 © 2015 Asian Pacific Society of Respirology
SUMMARY AT A GLANCE Despite efforts to differentiate between COPD and asthma, misdiagnosis is still a serious problem in general practice, especially in a primary care setting. This study suggests a new scoring system that may be a useful tool for differentiating between COPD and asthma in primary care.
Key words: asthma, chronic obstructive pulmonary disease, differential diagnosis, primary care physician. Abbreviation: ACOS, asthma–chronic obstructive pulmonary disease overlap syndrome; AUC, area under the receiver operating characteristic curve; CI, confidence interval; COPD, chronic obstructive pulmonary disease; CT, computed tomography; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PFT, pulmonary function test.
INTRODUCTION Chronic obstructive pulmonary disease (COPD) and asthma are leading causes of morbidity and mortality worldwide and associate with significant economic/ social burdens.1,2 COPD is usually characterized by progressive and irreversible airflow limitation, while asthma is characterized by airway hyperresponsiveness and reversible airflow limitation. In addition, the basis for COPD treatment is inhaled bronchodilator, except in patients at risk of recurrent exacerbations, while inhaled corticosteroid is used in asthma.1,2 Despite these differences between the two diseases, misdiagnosis is still a serious problem in general practice.1–5 Primary physicians often misdiagnose the two diseases because of a lack of proper diagnostic tools and difficulties in interpreting the spirometry data.6–9 Patients could be receiving incorrect therapy if they are misdiagnosed in primary care; as a result, they may experience a poor response to therapy and have a high risk of adverse events.9–11 For this reason, Respirology (2015) 20, 626–632 doi: 10.1111/resp.12511
New scoring system in COPD and asthma
many symptom-based questionnaires for differentiating COPD and asthma were developed.12–19 However, many of these questionnaires are very complex (e.g. they include many items), and the results cannot suggest an action plan. The aim of this study was to develop a scoring system that can be used as a tool to differentiate between COPD and asthma in primary care, and to evaluate its effectiveness. This scoring system may be useful for guiding primary physicians in the identification, treatment and follow-up care of COPD and asthma.
627 tor test). A reversible component was defined as a change of more than 400 mL, and achievement of at least 80% of the predicted FEV1 after bronchodilator or other treatments (including oral or inhaled high dose steroid), as assessed by follow-up PFT or bronchodilator test.4,24,25 Asthma was considered to be present in any patient who fulfilled one or more of the following criteria: (i) variability in the maximum diurnal peak expiratory flow (>20%) over the course of 14 days; (ii) the presence of a post-bronchodilator FEV1/FVC ≥0.70 or post-bronchodilator FEV1/FVC
