Prevalence of ACOS in the ethnic Kashmiri population and the exacerbation rate in this subset of COPD patients

Abstract

Background: COPD is now recognised as a disease with varied phenotypes with a considerable overlap between bronchial asthma and its one of the phenotypes namely asthma COPD-overlap syndrome (ACOS). The differentiation between asthma and chronic obstructive pulmonary in the early stage of disease is extremely important for the adoption of appropriate therapeutic measures.

Aims and Objectives:

The present study was undertaken to study the prevalence of ACOS in the ethnic Kashmiri population and the exacerbation rate in this subset of COPD patients.

Materials and methods:

This was a prospective study undertaken to study the frequency of ACOS among patients of obstructive airway disease in our ethnic population. Patients suspected of obstructive airway disease were subjected to a pulmonary function test (PFT) according to ATS/ERS guidelines. Airflow obstruction was defined by post bronchodilator FEV1/FVC ratio of <0.7.  In addition, sputum eosinophilic count, complete blood count and serum IgE levels were done in all patients.

Subsequently, patients were characterised into three groups based on the results of pulmonary function tests into COPD, asthma and ACOS. The data was analysed using pearsons chi- square t test, odds ratio with confidence interval(CI) 95% and p value of <0.05 was considered  to be statistically significant.

Results:

The prevalence ACOS in the present study was 17.7%. Our study included 130 stable patients of obstructive airway disease, which were assessed for the presence of asthma-COPD overlap syndrome, as per the criteria given by GES EPOC Spanish guidelines. Out of 130 patients 23 patients (17.7%) were found to have asthma-COPD overlap phenotype, 48 patients (37%) were asthmatics and 59 patients (45%) were COPD patients. Out of 23 patients of asthma –COPD overlap syndrome only 3 patients (13%) were having < 2 exacerbations / year and 20 patients (87%) were having ≥ 2 exacerbations /year. (p value<0.0001)

Conclusion: The asthma –COPD overlap (ACOS) patients represent a sizeable proportion of patients with obstructive airway disease and  have more frequent exacerbations as compared to patients of asthma or COPD alone.