Distinct asthma phenotypes with low maximal attainment of lung function on cluster analysis

Abstract

Objective

Asthma is a heterogeneous disease with varying clinical presentations, severity and ability to achieve asthma control. The present study aimed to characterize clinical phenotypes of asthma in an Indian cohort of subjects using a cluster analysis approach.

Methods

Patients with confirmed asthma (N = 100) and at least 6-months of follow-up data, identified by retrospective chart review, were included in this study. Demographics, age at disease onset, disease duration, body mass index, serial spirometry and allergen sensitization were assessed. Asthma control was assessed prospectively using Global Initiative for Asthma and Asthma Control Test. R version 3.4.3 was used for statistical analysis. Ward’s minimum-variance hierarchical clustering method was performed using an agglomerative (bottom-up) approach. To compare differences between clusters, analysis of variance using Kruskal-Wallis test (continuous variables) and chi-square test (categorical variables) was used.

Results

Cluster analysis of 100 treatment-naive patients with asthma identified four clusters. Cluster 1, (N = 40), childhood onset of disease, normal body weight, equal gender distribution and achieved normal lung function. Cluster 2 (N = 16) included adolescent disease-onset, obese, majority males and had poor attainment of maximum lung functions. Cluster 3 (N = 20) were older, late-onset of disease, obese, majority male and had poor attainment of maximum lung function. Cluster 4 (N = 24) had adult-onset of disease, obese, predominantly female and achieved normal lung function.

Conclusions

In an Indian cohort of well-characterized patients with asthma, cluster analysis identified four distinct clinical phenotypes of asthma, two of which had poor attainment of maximum lung functions.

Keywords:

• Lung function
• allergy
• treatment responsiveness
• genetics
• categorize

Declaration of interest

Dr. Sandhya K (Division of Pulmonary & Critical Care Medicine, University of Rochester Medical Center, Rochester, United States of America) has participated in clinical trials of biologicals with GSK and Sanofi.

Additional information

Notes on contributors

Smriti Bhargava

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Amrutha D. Holla

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Biligere S. Jayaraj

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Attahalli S. Praveena

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Sreenivasan Ravi

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Sandhya Khurana

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.

Padukudru A. Mahesh

S.B., A.D.H., B.S.J. and P.A.M. conceptualized, designed the study and collected the data. A.S.P., S.R., S.K. and P.A.M. were involved in data analysis. All authors contributed in the writing of the manuscript and reviewed the content critically.