Which breathlessness dimensions associate most strongly with fatigue? - The population-based VASCOL study of elderly men

Background: Breathlessness and fatigue are common symptoms in older people. We aimed to evaluate how different breathlessness dimensions (overall intensity, unpleasantness, sensory descriptors, emotional responses) were associated with fatigue in elderly men. Methods: This was a cross-sectional analysis of the population-based VAScular disease and Chronic Obstructive Lung Disease (VASCOL) study of 73-year old men. Breathlessness dimensions were assessed using the Dyspnoea-12 (D-12), Multidimensional Dyspnoea Profile (MDP), and the modified Medical Research Council (mMRC) scale. Fatigue was assessed using the Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-F) questionnaire. Clinically relevant fatigue was defined as FACIT-F≤ 30 units. Scores were compared standardized as z-scores and analysed using linear regression, adjusted for body mass index, smoking, depression, cancer, sleep apnoea, prior cardiac surgery, respiratory and cardiovascular disease. Results: Of 677 participants, 11.7% had clinically relevant fatigue. Higher breathlessness scores were associated with having worse fatigue; for D-12 total, -0.35 ([95% CI] -0.41 to -0.30) and for MDP A1, -0.24 (-0.30 to -0.18). Associations were similar across all the evaluated breathlessness dimensions even when adjusting for the potential confounders. Discussion: When assessing a correlation with fatigue, both questionnaires seem to work equally well. MDP A1 only comprise a single descriptor compared to the 12 descriptors in D-12 (total), which may help avoid unnecessary burden of assessments in people with more severe illness. When a clinician identifies a patient with severe breathlessness, our data suggests that they should ask about fatigue and vice versa. Conclusion: Breathlessness assessed using D-12 and MDP was associated with worse fatigue in elderly men, similarly across different breathlessness dimensions.