Minimal Clinically Important Differences and Feasibility of Dyspnea-12 and the Multidimensional Dyspnea Profile in Cardiorespiratory Disease

Context Breathlessness is a cardinal symptom in cardiorespiratory disease and consists of multiple dimensions that can be measured using the instruments Dyspnea-12 (D12) and the Multidimensional Dyspnea Profile (MDP). Objectives The objective of the study is to determine the minimal clinically important differences (MCIDs) of all D12 and MDP summary and subdomain scores as well as the instruments' feasibility in patients with cardiorespiratory disease. Methods Prospective multicenter cohort study of outpatients with diagnosed cardiorespiratory disease and breathlessness in daily life. D12 and MDP were assessed at baseline, after 30–90 minutes and two weeks. MCIDs were calculated using anchor-based and distributional methods for summary and subdomain scores. Feasibility was assessed as rate of missing data, help required, self-reported difficulty, and completion time. Results A total 182 outpatients (53.3% women) were included; main diagnoses were chronic obstructive pulmonary disease (COPD; 25%), asthma (21%), heart failure (19%), and idiopathic pulmonary fibrosis (19%). Anchor-based MCIDs were for D12 total score 2.83 (95% CI 1.99–3.66); D12 physical 1.81 (1.29–2.34); D12 affective 1.07 (0.64–1.49); MDP A1 unpleasantness 0.82 (0.56–1.08); MDP perception 4.63 (3.21–6.05), and MDP emotional score 2.37 (1.10–3.64). The estimates were consistent with small-to-moderate effect sizes using distributional analysis, and MCIDs were similar between COPD and non-COPD patients. The instruments were generally feasible and quick to use. Conclusion D12 and MDP are responsive to change and feasible for use for assessing multidimensional breathlessness in outpatients with cardiorespiratory disease. MCIDs were determined for use as endpoints in clinical trials.