MRC dyspnoea grade distribution by stage of airflow limitation (first MRC grade from study start).

<p>Abbreviations: COPD, chronic obstructive pulmonary disease; MRC, Medical Research Council. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 equals to mMRC 0.</p

Distribution of MRC dyspnoea grade in the COPD cohort (first MRC grade from the study start).

<p>Abbreviations: COPD, chronic obstructive pulmonary disease; MRC, Medical Research Council. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 equals to mMRC 0.</p

Frequency of exacerbation events during the 12-month study period (from first recorded MRC dyspnoea grade from study start).

<p>^ap-value estimated, using negative binomial regression, for a distribution of exacerbations between patients with a specific grade (MRC = 1, no dyspnoea is a referent category).</p><p>Abbreviation: MRC, Medical Research Council.</p

Comorbidities and respiratory medications in the total COPD cohort (at study start) further split by the MRC dyspnoea grade (first recorded from study start).

<p>Percentages are based on row total. Comorbidities were searched for any time in the history before the observation period start; respiratory medications were searched for 12 months prior to study start. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 equals to mMRC 0.</p><p>^a≥4 treatments per year.</p><p>Abbreviations: COPD, chronic obstructive pulmonary disease; ICS, inhaled corticosteroids; LABA, long-acting beta-blockers; LAMA, long-acting anticholinergics; MI, myocardial infarction; MRC, Medical Research Council; SABD, short-acting bronchodilators; SD, standard deviation.</p

Factors associated with level of dyspnoea. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 being equal to mMRC 0.

<p>^aOther smoker: no record about smoking history or record of passive smoking.</p><p>Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; GOLD, global initiative for obstructive lung disease; GP, general practitioner; MRC, Medical Research Council.</p

Cohort selection: flow diagram.

<p>Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁/FVC, forced expiratory volume in 1 second/forced vital capacity; GPRD, General Practice Research Database; MRC, Medical Research Council.</p

Medical Research Council dyspnoea grades (16).

<p>Adapted with permission from Fletcher CM, Elmes PC, Fairbairn MB, et al. The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population. <i>Br Med J</i> 1959; 2∶257–266, as used in the UK National Health Service Quality and Outcomes Framework for COPD (16).</p

Bivariate relationship between FEV_1% predicted and MRC grade: scatter plot.

<p>Abbreviations: FEV_1%predicted, forced expiratory volume in one second; Stage I: FEV₁≥80% predicted; Stage II: ≥50% to <80% FEV₁ predicted; Stage III: ≥30% to <50% FEV₁ predicted; Stage IV: >30% FEV₁ predicted; MRC, Medical Research Council. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 being equal to mMRC 0.</p

Demographics and clinical characteristics of the total COPD cohort (at observation period start) further split by the MRC dyspnoea grade (first recorded from study start).

<p>Percentages are based on row total. MRC scoring 1–5 equals to mMRC grades 0–4 with MRC 1 equals to mMRC 0.</p><p>^a Other smoker: no record about smoking history or record of passive smoking.</p><p>Data on BMI were missing for 865 (1.7%) patients.</p><p>Data on GOLD grade were missing for 1002 (2%) patients.</p><p>Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; GOLD, global initiative for obstructive lung disease; GP, general practitioner; MRC, Medical Research Council; SD, standard deviation.</p

Factors associated with risk of moderate-to-severe exacerbation during the 12-months’ follow-up (negative binomial regression).

<p>^aReferent group always constitutes patients without the trait anytime in their history prior to dyspnoea index date.</p><p>Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; GOLD, global initiative for obstructive lung disease; GP, general practitioner; MRC, Medical Research Council; QOF, UK National Health Service Quality and Outcomes Framework.</p