A list of measures included in the exploratory factor analysis model

1. Sex14. mMRC
2. Age15. EQ-5D-5L – Index
3. BMI16. FACIT – Fatigue Scale
4. Dyspnea-12 – Affect17. Average severity of pain
5. Dyspnea-12 – Physical18. CAT
6. MDP_A2_Anxiety19. MDP_A2_Depression
7. MDP_A2_Afraid20. MDP_A1_Breathing Discomfort
8. MDP_A2_Angry21. MDP_SQ1_Physical Effort
9. MDP_A2_Frustrated22. MDP_SQ2_Hunger
10. Breathlessness at rest23. MDP_SQ3_Tightness
11. Breathlessness mean24. MDP_SQ4_Mental Effort
12. HADS – Depression25. MDP_SQ5_Hypernoea
13. HADS – Anxiety

BMI: body mass index; MDP: multidimensional dyspnea profile; SQ: sensory dimension; A2: emotional response domain; HADS: hospital anxiety and depression scale; FACIT: functional assessment of chronic illness therapy – fatigue scale; mMRC: modified Medical Research Council breathlessness scale; CAT: COPD assessment test; EQ-5D–5L: EuroQol five dimensions – five levels.