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.