The modified Medical Research Council dyspnoea scale is a good indicator of health-related quality of life in patients with chronic obstructive pulmonary disease

INTRODUCTION Health-related quality of life (HRQoL) is an important patient-centred outcome in chronic obstructive pulmonary disease (COPD). The aim of the current study is to compare the discriminative capacity of the modified Medical Research Council (mMRC) dyspnoea scale and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric classification of COPD on HRQoL, as well as determine other factors that are simple and determinative of HRQoL. METHODS In this cross-sectional observational study, a total of 328 patients with COPD were enrolled from the pulmonology outpatient clinic. HRQoL was measured using the St George's Respiratory Questionnaire (SGRQ) and the World Health Organization Quality of Life-BREF (WHOQOL-BREF). HRQoL scores were compared between the four GOLD stages and the five grades of the mMRC scale. Significant differences were determined using analysis of variance with Scheffe post-hoc test. Multiple linear regression was applied to explore the major determinants of HRQoL and exclude confounding factors. RESULTS Significant differences were found in many more domains of the two questionnaires between mMRC grades than between GOLD stages. In the multiple linear regression model, the mMRC scale was the only factor that remained determinative of all the domains of SGRQ and WHOQOL-BREF. Patients with chronic productive cough, sleep disorders and frequent exacerbations had poorer HRQoL, as reflected by higher scores in SGRQ or lower scores in WHOQOL-BREF. CONCLUSION The mMRC dyspnoea scale is a concise and practical tool to assess the HRQoL of patients with COPD in daily clinical practice.