Heterogeneity of asthma and COPD overlap
Received 29 September 2017
Accepted for publication 19 February 2018
Published 17 April 2018 Volume 2018:13 Pages 1251—1260
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Charles Downs
Peer reviewer comments 3
Editor who approved publication: Dr Richard Russell
Min-Hye Kim,1 Chin Kook Rhee,2 Kyungjoo Kim,2 Sang Hyun Kim,3 Jung Yeon Lee,4 Yee Hyung Kim,5 Kwang Ha Yoo,6 Young-Joo Cho,1 Ki-Suck Jung,7 Jin Hwa Lee1
1Department of Internal Medicine, College of Medicine, Ewha Womans University, 2Department of Internal Medicine, Seoul St Mary’s Hospital, The Catholic University of Korea, Seoul, 3Big Data Division, Health Insurance Review and Assessment Service, Wonju, 4Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju, 5Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 6Department of Internal Medicine, Konkuk University College of Medicine, Seoul, 7Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, Republic of Korea
Background: Asthma and COPD are heterogeneous diseases. Patients with both disease features (asthma–COPD overlap [ACO]) are common. However, clinical characteristics and socio-economic burden of ACO are still controversial. The aim of this study was to identify the heterogeneity of ACO and to find out the subtypes with clinical impact among ACO subtypes.
Methods: In the Korean National Health and Nutrition Examination Survey (KNHANES) conducted between 2007 and 2012, subjects who were ≥40 years and had prebronchodilator FEV1/FVC <0.7 and FEV1 ≥50% predicted were included. The presence or absence of self-reported wheezing was indicated by W+ or W- and used as an index of airway hyper-responsiveness. S+/S- was defined as subjects who were smokers/never smokers. The subjects were divided into the following four groups: W-S-, W-S+, W+S-, and W+S+. W+S- and W+S+ were asthma-predominant ACO and COPD-predominant ACO, respectively. KNHANES and linked National Health Insurance data were analyzed.
Results: The asthma-predominant ACO group showed the lowest socioeconomic status, FEV1, FVC% predicted, and quality of life (QoL) levels. The COPD-predominant ACO group showed the highest hospitalization rate, outpatient medical cost, and total and outpatient health care utilization. COPD-predominant ACO was associated with exacerbations compared to the W-S- group (adjusted odds ratio [aOR], 1.79; 95% confidence interval [CI], 1.12–2.85; P=0.015) and W-S+ group (OR 2.11; 95% CI 1.43–3.10; P<0.001). COPD-predominant ACO was associated with increased medical cost.
Conclusion: Asthma-predominant ACO individuals displayed poorer socioeconomic status and QoL compared to the COPD-predominant ACO group. The COPD-predominant ACO group displayed more frequent exacerbations and greater medical costs. Considering the heterogeneity of ACO, it is desirable to identify subtypes of ACO patients and appropriately allocate limited medical resources.
Keywords: asthma, COPD, overlap, heterogeneity, health care utilization, exacerbation
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