Prevalence and characteristics of asthma-chronic obstructive pulmonary disease overlap among asthma and chronic obstructive pulmonary disease patients in a tertiary care center in Northeast India

Abstract

Introduction: There is an increasing awareness of a subgroup of patients with chronic airway obstruction which shares several features of asthma as well as chronic obstructive pulmonary disease (COPD) known as asthma-COPD overlap (ACO). There are limited studies on the characteristics of this subgroup while the disease tends to be more severe in them compared to those with asthma or COPD alone. The aim of this study is to determine the prevalence and clinical and sociodemographic profile of ACO. Materials and Methods: This is a single-center, cross-sectional study over a 2-year period from September 2016 to October 2018. Patients above 40 years of age attending our center for the treatment of asthma or COPD in the study period were enrolled. Using the stepwise syndromic approach stated in the recent Global Initiative for Asthma guidelines, they were classified into the groups: asthma, COPD, or ACO. Results: Of the 164 patients enrolled, 37 (22.6%) were found to have ACO. Among patients with ACO, 21 (56.8%) were female (P = 0.016). The prevalence was highest in the age group of 51–60 years, and 31 (83.8%) were smokers/ex-smokers. Majority (43.5%) had normal body mass index. The mean forced expiratory volume in 1 (FEV1) (pre- and postbronchodilation) was lower for patients with ACO (1.4 ± 0.482 and 1.6 ± 0.391) compared to asthma/COPD alone (1.7 ± 0.663 and 1.8 ± 0.682) but was not clinically significant. The postbronchodilation FEV1/forced vital capacity was significantly lower for ACO (69.4 ± 13.2) compared to asthma/COPD alone (72.9 ± 12.7). Twenty-five (67.5%) patients had reversibility. Conclusion: Using the syndromic approach, the prevalence of ACO was found to be 22.6%. Significantly more females and smokers/ex-smokers present with ACO. Patients with ACO have worse lung function than those with asthma/COPD alone.