Beyond Breathlessness Intensity: A Prospective Psychometric Validation of the Multidimensional Dyspnea Profile in Heart Failure with Reduced and Mildly Reduced Ejection Fraction

Background/Objectives: Dyspnoea in heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) is multidimensional, yet conventional unidimensional scales do not capture its sensory and affective components. The Multidimensional Dyspnea Profile (MDP) addresses this gap; however, its psychometric properties have not been established in a dedicated HFrEF/HFmrEF cohort. We assessed structural validity, internal consistency, test–retest reliability, and construct validity of the MDP using COSMIN methodology. Methods: In this prospective, single-centre psychometric validation study, 101 clinically stable adults with HFrEF or HFmrEF were enrolled at a tertiary outpatient cardiac clinic in Riyadh, Saudi Arabia. Participants completed the MDP alongside Dyspnea-12, modified Medical Research Council scale, Kansas City Cardiomyopathy Questionnaire-12, Fatigue Severity Scale, and 6 min walk test. Test–retest data were obtained at 12 days in patients confirmed stable by the Global Rating of Change (n = 87). Psychometric evaluation included Cronbach’s α, intraclass correlation (ICC2,1), standard error of measurement, minimum detectable change (MDC95), confirmatory factor analysis (comparative fit index [CFI], root mean square error of approximation [RMSEA], standardised root mean square residual [SRMR]), and 12 a priori construct hypotheses. A preliminary minimal clinically important difference (MCID) was estimated using anchor- and distribution-based methods. Results: The mean age was 55 ± 11 years and 80% were male. CFA supported the two-factor model (CFI = 0.96; RMSEA = 0.061; SRMR = 0.058). Cronbach α was 0.92 for the full scale, 0.88 for immediate perception, and 0.91 for emotional response. ICC2,1 was 0.94 (95% CI: 0.91–0.96), and MDC95 was 4.2 points. All 12 hypotheses were confirmed. The preliminary MCID was 8 points. Conclusions: The MDP is a reliable, valid, and clinically interpretable multidimensional dyspnoea measure in HFrEF/HFmrEF. The 8-point MCID is preliminary and requires confirmation in larger longitudinal intervention studies.