The Relationship Between Clinical Phenotypes and Global Initiative for Chronic Obstructive Lung Disease (GOLD) Stages/Groups in Patients With Chronic Obstructive Pulmonary Disease.

Background Chronic obstructive pulmonary disease (COPD) cannot be properly characterised by a single metric, forced expiratory volume in the first second (FEV1), due to its complexity and heterogeneity. The GOLD 2017 report contained the ABCD evaluation method to measure airflow limitation, symptoms, and/or exacerbation risk. Objective The purpose of this study was to explore the relationship between clinical characteristics and GOLD groups or stages in patients with COPD. Methods This cross-sectional observational study was conducted at the department of respiratory medicine, King George's Medical University, Lucknow, Uttar Pradesh, India, between 2019 and 2022. Here, stable COPD patients' demographics, clinical characteristics, and the number of exacerbations were compared between the groups following the GOLD 2022 report. An unpaired t-test with Welch's correction, chi-square test, Fisher's exact test, one-way ANOVA, and Kruskal-Wallis test were used for statistical significance. Results In this study, 349 stable COPD patients (256 males and 93 females) were selected. The GOLD 2017 categorization placed 78 (22.4%) patients in group A, 158 (45.3%) in B, 44 (12.6%) in C, and 69 (19.8%) in D. Further, we used GOLD 2017 to classify COPD patients into 16 subgroups (1A-4D). FEV1 (% predicted) decreased across groups A to D (p<0.0001). Groups C and D had a longer duration of illness, higher COPD assessment test (CAT) score, higher Modified Medical Research Council (mMRC) dyspnea scale, longer exacerbation history, and more COPD hospitalizations in the previous year than groups A and B. More symptomatic patients (B and D) exhibited lower FEV1 (% predicted) and more severe airflow limitation than less symptomatic patients (A and C) (p=0.0002). Symptomatic individuals exhibited higher CAT and mMRC dyspnea scores (p<0.0001). Groups C and D comprised older patients and those with longer disease duration, higher mMRC dyspnea scale and CAT, lower FEV1, and more severe airflow limitation (A and B). Conclusion The present study demonstrates the distribution of COPD patients' clinical phenotypes in an Indian population. We conclude that the combined COPD assessment according to the GOLD 2022 guideline provides a better understanding of COPD.