Evaluation of the Modified Medical Research Council Dyspnea Scale for Predicting Hospitalization and Exacerbation in Japanese Patients with Chronic Obstructive Pulmonary Disease

Objective The modified Medical Research Council (mMRC) scale is recommended for conducting assessments of dyspnea and disability and functions as an indicator of exacerbation. The aim of this study was to investigate whether the mMRC scale can be used to predict hospitalization and exacerbation in Japanese patients with chronic obstructive pulmonary disease (COPD). Methods In a previous 52-week prospective study, 123 patients with COPD were classified into five groups (grades 0 to 4) according to the mMRC scale and four groups (stages I to IV) according to the spirometric Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. The frequency and period until the first event of hospitalization and exacerbation were compared among the groups. Results The population of patients who experienced hospitalization and exacerbation during the 52-week study period, with an mMRC scale grade of 4, 3, 2, 1 and 0 was 50.0 and 100, 55.6 and 88.9, 21.1 and 73.7, 2.6 and 48.7, and 4.0 and 22.0%, respectively. A multivariate analysis adjusted for the GOLD stage and age showed that the patients with an mMRC scale grade of >= 3 had higher frequencies of hospitalization and exacerbation than those with lower grades. Meanwhile, the patients with an mMRC scale grade of >= 2 showed a significantly earlier time until the first exacerbation, but not hospitalization, in comparison with those with grade 0. Conclusion The present results indicate that, among Japanese patients with COPD, those with an mMRC scale grade of >= 3 have a significantly poorer prognosis and that the mMRC scale can be used to predict hospitalization and exacerbation.