Association Between Dietary Adherence and Cognitive Function Among Rural Older Patients with Cardiometabolic Multimorbidity: The Moderating Role of Health Management

<b>Background:</b> Cardiometabolic multimorbidity (CMM) among rural older adults is becoming increasingly prevalent. Although previous studies have confirmed that dietary adherence significantly affects cognitive function, the mechanisms underlying this relationship remain insufficiently explored. This cross-sectional study aimed to examine the association between dietary adherence and cognitive function among rural older patients with CMM and further explored the moderating role of health management. <b>Methods:</b> The sample was selected using a multi-stage cluster random sampling method and a total of 1487 rural older patients with CMM were ultimately included. Hierarchical regression analysis was employed to examine the association between dietary adherence and cognitive function and test the moderating role of health management. Simple slope analysis was further employed to explore the moderation effect. <b>Results:</b> The cognitive function and dietary adherence scores of rural older patients with CMM were 20.790 ± 6.278 and 2.157 ± 0.286, respectively. Dietary adherence was significantly and positively associated with cognitive function (β = 2.000, <i>p</i> < 0.001) and health management moderated this relationship (β = 4.287, <i>p</i> = 0.009). Compared with rural older patients with CMM who did not receive health management, the positive predictive effect of dietary adherence on cognitive function was significantly stronger among those who received health management. <b>Conclusions:</b> Higher dietary adherence was positively associated with better cognitive function among rural older patients with CMM, and receiving health management further strengthened this association. These findings emphasized the importance of integrating dietary guidance within community-based health management interventions to promote cognitive function.