The modified Medical Research Council (mMRC) Scale
- Fysiobasen
- Sep 18
- 3 min read
Dyspnea, often referred to as shortness of breath, is a common symptom in both respiratory and cardiovascular diseases. It is a subjective experience that can reduce quality of life and functional capacity, and the degree of dyspnea provides important information about disease severity and treatment needs【1】.
The modified Medical Research Council (mMRC) scale is a simple and widely recognized tool for assessing how dyspnea affects daily activities. The scale is included in numerous clinical guidelines and is frequently used in practice due to its intuitive and easy-to-use design【2】.
Target population
The mMRC scale is relevant for patients with a wide range of conditions:
Chronic obstructive pulmonary disease (COPD)
Asthma
Restrictive lung diseases
Pulmonary fibrosis
Heart failure and other cardiovascular conditions【3】
Occupational lung diseases
Obesity-related breathing problems
Neuromuscular diseases【4】
Use and structure
The scale is a self-report tool in which patients rate dyspnea from 0 to 4, based on activities that trigger shortness of breath:
Grade 0: No dyspnea except with strenuous physical activity.
Grade 1: Shortness of breath when hurrying on level ground or walking up a slight hill.
Grade 2: Walks slower than peers on level ground or has to stop for breath when walking at normal pace.
Grade 3: Stops for breath after about 100 meters or a few minutes on level ground.
Grade 4: Too breathless to leave the house, or short of breath when dressing/undressing【5】.
This simple structure makes the scale quick to administer and easy to understand for both patients and healthcare providers【6】.
Evidence and clinical significance
The mMRC scale is strongly supported by research:
Strong correlation with patient-reported quality of life, especially in COPD【7】.
Predicts important outcomes such as hospitalizations and mortality【8】.
Higher scores indicate reduced physical activity and poorer quality of life.
This makes it a valuable decision-support tool for clinicians.
Advantages and limitations
Advantages:
Simple and quick to use
Requires minimal training
Useful for monitoring progression over time
Widely available in both clinical and research contexts【9】
Limitations:
Dependent on subjective patient assessment
May overlook small changes in symptom progression
Less sensitive for research when detecting subtle changes【10】
Clinical use
The mMRC scale is often used in combination with other assessment tools:
Spirometry: To assess lung function
Quality of life scales: To capture overall patient status
Functional tests: For example, the 6 Minute Walk Test
This combined approach provides a more comprehensive overview of the patient’s condition and helps guide treatment and follow-up. The scale also helps identify patients requiring more intensive treatment or daily support【11】.
Conclusion
The modified MRC scale is an indispensable tool in the assessment of dyspnea. It is simple, quick, clinically useful, and strongly correlated with patient function and quality of life. Despite its limitations, the scale is particularly valuable for the follow-up of patients with chronic respiratory conditions, contributing to targeted treatment and more efficient resource use【12】.
Sources:
1. Sunjaya A, Poulos L, Reddel H, Jenkins C. Qualitative validation of the modified Medical Research Council (mMRC) dyspnoea scale as a patient-reported measure of breathlessness severity. Respiratory Medicine. 2022;203:106984.
2. Rajala K, Lehto JT, Sutinen E, Kautiainen H, Myllärniemi M, Saarto T. mMRC dyspnoea scale indicates impaired quality of life and increased pain in patients with idiopathic pulmonary fibrosis. ERJ Open Research. 2017;3(4).
3. Williams N. The MRC breathlessness scale. Occupational Medicine. 2017;67(6):496-7.
4. Hsu KY, Lin JR, Lin MS, Chen W, Chen YJ, Yan YH. The modified Medical Research Council dyspnoea scale is a good indicator of health-related quality of life in patients with chronic obstructive pulmonary disease. Singapore Medical Journal. 2013;54(6):321-7.
5. Munari AB, Gulart AA, Dos Santos K, Venâncio RS, Karloh M, Mayer AF. Modified medical research council dyspnea scale in GOLD classification better reflects physical activities of daily living. Respiratory Care. 2018;63(1):77-85.
6. Perez T, Burgel PR, Paillasseur JL, Caillaud D, Deslée G, Chanez P, Roche N. Modified Medical Research Council scale vs Baseline Dyspnea Index to evaluate dyspnea in chronic obstructive pulmonary disease. International Journal of Chronic Obstructive Pulmonary Disease. 2015;10:1663-72.
7. Chhabra SK, Gupta AK, Khuma MZ. Evaluation of three scales of dyspnea in chronic obstructive pulmonary disease. Annals of Thoracic Medicine. 2009;4(3):128.
8. Hayata A, Minakata Y, Matsunaga K, Nakanishi M, Yamamoto N. Differences in physical activity according to mMRC grade in patients with COPD. International Journal of Chronic Obstructive Pulmonary Disease. 2016;11:2203-8.
9. Yasui H, Inui N, Karayama M, et al. Correlation of the modified Medical Research Council dyspnea scale with airway structure assessed by three-dimensional CT in patients with chronic obstructive pulmonary disease. Respiratory Medicine. 2019;146:76-80.
10. Chen H, Li Y, Wang W, Zhang H, Nie N, Ou J, Li L. Reliability and validity of the multidimensional dyspnea profile in hospitalized Chinese patients with respiratory diseases. SAGE Open Medicine. 2021;9:2050312120965336.
11. Sandberg J, Johnson MJ, Currow DC, Ekström M. Validation of the dyspnea exertion scale of breathlessness in people with life-limiting illness. Journal of Pain and Symptom Management. 2018;56(3):430-5.
