Better compliance to a personalized physical activity program optimizes physical fitness in HFpEF: a sub-analysis from the PRIORITY study

Abstract Background Physical activity is a key intervention for improving health outcomes across the continuum of heart failure with preserved ejection fraction (HFpEF). Despite its benefits, uptake and compliance remain limited. The PRIORITY trial was designed to evaluate the effectiveness of a partially supervised and remotely guided personalized exercise and physical activity intervention in patients with different stages of HFpEF. Purpose This sub-analysis of PRIORITY evaluates if differences in compliance to a hybrid exercise and physical activity intervention affects improvements in physical fitness in patients with HFpEF after the first phase (i.e. 4 months). Methods total of 156 HFpEF patients were randomized to the intervention group. All received a hybrid intervention combining 10 supervised sessions with a home-based remotely monitored (Garmin Forerunner S45) physical activity programme. Compliance in the first 4 months was assessed in 107 patients using weekly TRIMP (training volume × intensity across HR zones based on HR@VAT), and spectral clustering was applied. Physical fitness variables were measured at baseline (M0) and four months (M4) by means of cardiopulmonary exercise test. The Kruskal–Wallis test assessed differences between clusters at M0, M4 and for Δ (M4-M0), while paired t-tests evaluated within-group changes. Fisher’s exact test assessed associations between gender and HF stage. To examine differential responses over time, a two-way ANOVA was performed with Δ as the dependent variable and the cluster, HF stage and their interaction as factors. Finally, a linear mixed-effects models with time, cluster, and their interaction as fixed effects and patient ID as a random intercept was applied. Results Spectral clustering identified two clusters (Figure 1): 49 highly compliant and 58 low compliant, with mean TRIMP of 403 and 73, respectively. No differences in HFpEF stage, sex, age and VO2 peak were found between clusters. At baseline, compliant patients had lower HR at ventilatory anaerobic threshold (HR@VAT) (92.6±14.2 vs. 108.5±18.9 bpm, p 0.0001). Regarding Δ, high compliant patients improved HR@VAT whereas low compliant patients showed a reduction (3.7±9.9, -5.35±16.7 bpm, p = 0.0005) (Table 1). ANOVA on Δ showed cluster-dependent changes in VO2VAT (absolute and relative), workload at VAT, and HR@VAT, with HF stage additionally affecting Δ VO2VAT and workload. A Cluster × HF-stage interaction was observed for predicted %VO2 measures. Mixed-effects models confirmed significant Time×Cluster interactions for VO2VAT, workload at VAT, and HR@VAT, indicating differing submaximal responses over time. Conclusion Higher compliance with the hybrid intervention was associated with greater short-term improvements in physical fitness. These findings highlight the importance of personalized exercise programs to enhance engagement. Longer follow-up is needed to determine the long-term impact of compliance on HFpEF outcomes.Figure 1For image description, please refer to the figure legend and surrounding text. Table 1For image description, please refer to the figure legend and surrounding text.