Fluid intake adherence and its associated factors in patients receiving maintenance hemodialysis: a cross-sectional study utilizing the COM-B model

Background Controlling fluid intake plays an important role in reducing complications and mortality among patients receiving maintenance hemodialysis (MHD). The Capability-Opportunity-Motivation-Behavior (COM-B) model provides a theoretical framework for understanding the factors that influence health behavior. However, few studies have applied this model to investigate the factors associated with fluid intake adherence among patients receiving maintenance hemodialysis. Methods From February to April 2026, a questionnaire survey was conducted among 411 patients receiving maintenance hemodialysis. Fluid intake adherence was assessed using the Fluid Intake Adherence Scale. The COM-B model was used as the theoretical framework, and potential related factors were assessed using a general information questionnaire, a Hemodialysis Knowledge Questionnaire, a Family Care Scale, and a Chronic Disease Management Self Efficacy Scale. Results The fluid intake adherence score among patients receiving maintenance hemodialysis was 18.57 ± 4.81, indicating a moderate level of adherence. Multiple linear regression analysis identified five significant factors associated with fluid intake adherence ( R ² = 0.519), hemodialysis knowledge, family support, and self efficacy were positive correlates, whereas obesity and a dialysis frequency other than three times per week were negative correlates. Pathway analysis showed that hemodialysis knowledge and family support were directly associated with fluid intake adherence (direct effects of 0.331 and 0.463, P  < 0.05) and were also indirectly associated with fluid intake adherence through self efficacy (indirect effects of 0.175 and 0.104, P  < 0.05). Conclusions Interventions based on the COM-B model should focus on disease knowledge education, opportunity support, and motivation, with particular attention to improving self efficacy. These strategies may help improve fluid intake adherence and quality of life among patients receiving maintenance hemodialysis.