Clinical Significance of Asthma Clusters by Longitudinal Analysis in Korean Asthma Cohort

So Young Park,Hee-Bom Moon,You Sook Cho,Young-Joo Cho,Hyouk-Soo Kwon,Jung Won Park,Tae-Bum Kim,Seunghee Baek,Dong-Ho Nahm,Sang-Heon Cho,An-Soo Jang,Byoungwhui Choi,Ho-Joo Yoon,Sujeong Kim,Sun-Young Yoon,Yoon-Seok Chang,Tesfaye Mersha Baye

doi:10.1371/journal.pone.0083540

Abstract

BackgroundWe have previously identified four distinct groups of asthma patients in Korean cohorts using cluster analysis: (A) smoking asthma, (B) severe obstructive asthma, (C) early-onset atopic asthma, and (D) late-onset mild asthma.Methods and ResultsA longitudinal analysis of each cluster in a Korean adult asthma cohort was performed to investigate the clinical significance of asthma clusters over 12 months.Cluster A showed relatively high asthma control test (ACT) scores but relatively low FEV1 scores, despite a high percentage of systemic corticosteroid use. Cluster B had the lowest mean FEV1, ACT, and the quality of life questionnaire for adult Korean asthmatics (QLQAKA) scores throughout the year, even though the percentage of systemic corticosteroid use was the highest among the four clusters. Cluster C was ranked second in terms of FEV1, with the second lowest percentage of systemic corticosteroid use, and showed a marked improvement in subjective symptoms over time. Cluster D consistently showed the highest FEV1, the lowest systemic corticosteroid use, and had high ACT and QLQAKA scores.ConclusionOur asthma clusters had clinical significance with consistency among clusters over 12 months. These distinctive phenotypes may be useful in classifying asthma in real practice.

Highlights

Asthma is a clinical syndrome of intermittent respiratory symptoms characterized by chronic airway inflammation, nonspecific bronchial hyperresponsiveness, and reversible airway obstruction [1]
Longitudinal outcome measures We investigated the longitudinal trend of clinical status in terms of forced expiratory volume in 1 second (FEV1)% predicted, asthma control test (ACT) score [13], percentage of systemic corticosteroid use, and quality of life questionnaire for adult Korean asthmatics (QLQAKA) score [14] for each predefined cluster
In order to check if improvement of FEV1 seen in cluster B represents loss of data from patients with a low baseline FEV1, we compared the mean values of last recorded FEV1 between patients who revisited the clinic and those who did not at each follow up point, we found no significant differences of the last recorded FEV1 at 3, 6, 9 months and interestingly, at 12 month, the mean value of last recorded FEV1 in the patients who did not revisit clinic was significantly higher than those who did

Summary

Introduction

Asthma is a clinical syndrome of intermittent respiratory symptoms characterized by chronic airway inflammation, nonspecific bronchial hyperresponsiveness, and reversible airway obstruction [1]. Recent treatment guidelines emphasize the asthma control status, a convenient approach that can be applied clinically [1] Both the asthma control and severity have demonstrated critical drawbacks by failing to reflect the heterogeneous nature of asthma, which is determined by individually distinct pathophysiological backgrounds [3,4,5]. In our previous study [9], we used cluster analysis to identify four distinct groups of asthma in two large independent cohorts of Korean adult asthma patients: (A) smoking asthma, (B) severe obstructive asthma, (C) early-onset atopic asthma, and (D) lateonset mild asthma. We have previously identified four distinct groups of asthma patients in Korean cohorts using cluster analysis: (A) smoking asthma, (B) severe obstructive asthma, (C) early-onset atopic asthma, and (D) late-onset mild asthma

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Conclusion