An Assessment of Various Phenotypes of Chronic Obstructive Pulmonary Disease

Abstract

Context: Chronic obstructive pulmonary disease (COPD) is a multifactorial and heterogeneous disease. To approach this heterogeneity, an attempt to group patients with similar characteristics that could be associated with a differential clinical outcome has been done by using the term clinical phenotype. Aim: This study aimed to classify phenotypes of COPD, assess and compare demography, assess and compare functional status and comorbidities. Patients and Methods: A hundred stable COPD patients were studied to identify various phenotypes of COPD, clinical assessment (modified Medical Research Council grading), functional assessment (6-min walk test), spirometry (fraction of exhaled breath nitric oxide, diffusing capacity for carbon monoxide) and radiological assessment (high-resolution computerized tomography, echocardiography) and screening for obstructive sleep apnea by Berlin questionnaire. Chi-square test/Fisher's exact test was used for the analysis of qualitative data. Results: The mean age of subjects was 60.8 ± 9.2 years with male-to-female ratio 9:1. Out of total 100 COPD patients, 45% had emphysema phenotype, 15% had COPD with bronchiectasis, and 20% each had asthma COPD overlap and chronic bronchitis. COPD phenotype was most common in age group 56–65 years. Emphysema patients (48.6%) were underweight and obesity was found to be most common in chronic bronchitis (30%). Emphysema patients (91%) had maximum exacerbation during the past 1 year with mean 6-min walk distance (158.7 m) and mean forced expiratory volume in 1% was 37.5. Conclusion: This is the first study in India which provides comparative categorizations of the phenotypic subgroups of COPD on various parameters.