Associations between uncertainty in illness and cardiac rehabilitation adherence in patients with CHD: a cross-sectional chain mediation and latent profile analysis of cardiac self-efficacy and fear of activity.

OBJECTIVE: This study aimed to integrate variable-centered and person-centered approaches to examine the relationship between uncertainty in illness and cardiac rehabilitation adherence in patients with coronary heart disease (CHD), as well as the underlying psychological mechanisms involved. In addition, the study sought to identify latent subgroups of uncertainty in illness and to compare differences across these subgroups. METHODS: A cross-sectional study was conducted from August 2024 to April 2025. Patients with CHD were recruited from the departments of cardiology and cardiac rehabilitation centers of three hospitals in Shanxi Province, China. RESULTS: In the variable-centered analysis, uncertainty in illness was significantly and negatively associated with cardiac rehabilitation adherence, with a direct association coefficient of -0.119. Cardiac self-efficacy and fear of activity were involved in a statistically significant sequential indirect association. In the person-centered analysis, latent profile analysis identified three subgroups of uncertainty in illness: a cognitively clear-low uncertainty group (26.27%), a partially informed-moderate uncertainty group (39.41%), and a cognitively ambiguous-high uncertainty group (34.32%). Significant differences were observed among the three subgroups in cardiac self-efficacy, fear of activity, and cardiac rehabilitation adherence. CONCLUSION: Clinicians should systematically assess the level of uncertainty in illness among patients with CHD at the initial stage of cardiac rehabilitation and develop tailored, stratified intervention strategies for different subgroups. In particular, patients classified in the cognitively ambiguous-high uncertainty group should be provided with comprehensive informational support, self-efficacy enhancement training, and cognitive-behavioral interventions targeting fear of activity, so as to effectively improve cardiac rehabilitation adherence in this population.