Who benefits most from motivational interviewing in heart failure? The moderating role of ejection fraction

Abstract Background Motivational interviewing (MI) is an effective strategy to enhance self-care in heart failure (HF), yet intervention effects are heterogeneous. Left ventricular ejection fraction (EF), a key marker of HF phenotype and clinical complexity, may influence responsiveness to behavioural interventions, but its moderating role has been rarely examined. Purpose To evaluate whether EF moderates the effect of a nurse-delivered MI intervention on self-care maintenance (i.e., behaviours to maintain HF stability), management (i.e., behaviours to monitor and manage symptoms), and confidence (i.e., self-efficacy in self-care) in patients with HF. Methods This is a secondary analysis of the MOTIVATE-HF randomized controlled trial. Patients with HF were randomized to an MI-based intervention or usual care and followed up for 12 months. Self-care was assessed at baseline and at 3, 6, 9, and 12 months using the Self-Care of Heart Failure Index (SCHFI v.6.2), which has a 0-100 score, with higher score meaning better self-care and a clinically meaningful change of 8 points. Population-averaged generalized estimating equations were used to model longitudinal changes, adjusting for baseline self-care scores. EF was tested as a continuous moderator, with sensitivity analyses using guideline-based EF categories (reduced, mildly reduced, preserved). Results The analysis included 510 patients (mean age = 72.4 years; 42% women). Compared with usual care, MI significantly improved self-care maintenance and self-care confidence over time, while no consistent effect emerged for self-care management. EF significantly moderated the intervention effect for maintenance and confidence: lower EF was associated with larger and more sustained benefits from MI, whereas effects were attenuated at higher EF levels. Each 10% increase in EF reduced the MI-related advantage by approximately 5–6 points for maintenance and up to 10 points for confidence at later follow-ups. Findings were consistent in sensitivity analyses using EF categories. Conclusions MI improves key dimensions of HF self-care, particularly maintenance and confidence, and its effectiveness is moderated by EF. Patients with reduced EF appear to benefit most, whereas those with preserved EF—often characterized by multimorbidity and greater complexity—show attenuated responses. These findings support a phenotype-informed approach to behavioural interventions in HF and suggest the need to tailor MI-based strategies according to EF levels.