Agreement Between Breathlessness Severity and Unpleasantness in People With Chronic Breathlessness: A Longitudinal Clinical Study

Context: Chronic breathlessness is a cardinal symptom in cardiopulmonary disease where both overall intensity or severity (S) and unpleasantness (U) are commonly quantified. Objective: We aimed to evaluate agreement between breathlessness severity and unpleasantness over eight days in patients with chronic breathlessness. Methods: Longitudinal analysis of 265 patients with chronic breathlessness who rated current overall breathlessness severity and unpleasantness on a 0–100 mm visual analogue scale (VAS) in the morning and evening over eight days. A total of 3630 paired overall severity-unpleasantness (S−U) differences were analyzed; median 15 (IQR 13–16) per patient. Agreement was evaluated using Bland-Altman plots. Associations of the difference between severity and unpleasantness (S−U difference) with clinical factors and perceived quality of life were analyzed using multilevel linear regression adjusted for confounders. Results: Over eight days, severity and unpleasantness scores were highly correlated, had similar variability, and varied more between patients than within patients. The mean S−U difference was small at 2.1 mm. Agreement between overall severity and unpleasantness was similar or higher than expected from the variability in individual scores. The S−U difference was similar across evaluated factors including age, sex, diagnosis, morning/evening assessment, modified Medical Research Council breathlessness score, morphine treatment, and presence of different sensory qualities of breathlessness. Higher overall severity and unpleasantness associated with worse perceived quality of life in a similar way. Conclusion: In patients with chronic breathlessness over eight days, overall severity and unpleasantness of breathlessness were comparable and associated to other clinical factors in a similar manner.