Optimising diet to improve gut microbiota: association of the dietary index for gut microbiota with advanced cardiovascular-kidney-metabolic syndrome and adverse outcomes

Background Cardiovascular-kidney-metabolic (CKM) syndrome is a systemic pathological state, with its advanced stages (stages 3-4) inextricably linked to high mortality and healthcare burdens. The gut microbiome plays a pivotal role in CKM progression by modulating host metabolism and inflammation. While the Dietary Index for Gut Microbiota (DI-GM) quantifies the potential impact of diet on gut health, its association with the risk of advanced CKM and long-term patient outcomes remains undefined. Purpose To elucidate the association between the DI-GM and the prevalence of advanced CKM syndrome, and to evaluate its impact on all-cause and cardiovascular mortality in patients with advanced CKM. Methods A cross-sectional and prospective cohort analysis was conducted using the National Health and Nutrition Examination Survey (NHANES) database. DI-GM scores were calculated from 24-hour dietary recalls, and CKM stages were defined clinically. Primary endpoints were the prevalence of advanced CKM, all-cause mortality, and cardiovascular mortality. Multivariable logistic regression evaluated the association between DI-GM and advanced CKM prevalence. In 2,982 patients with advanced CKM, Kaplan-Meier curves and multivariable Cox proportional hazards models were utilised to assess mortality risks, adjusting for key demographic, lifestyle, and clinical confounders. Results The median DI-GM score was significantly lower in the advanced CKM group than in the non-advanced group (4.00 vs. 5.00, P<0.001). Adjusted multivariable logistic regression (Figure 1) demonstrated that each 1-unit increase in DI-GM score was associated with a 5% reduced odds of advanced CKM (OR 0.95, 95% CI: 0.90-0.99, P=0.033). Participants with the lowest scores (0-3) exhibited a 26% higher risk of advanced CKM compared to those scoring ≥6 (OR 1.26, 95% CI: 1.01-1.57, P=0.037). Among 2,982 patients with advanced CKM, a higher DI-GM score independently predicted lower mortality (Figure 2). Each 1-unit increase reduced all-cause mortality risk by 10% (HR 0.90, 95% CI: 0.83-0.97, P=0.005) and cardiovascular mortality risk by 20% (HR 0.80, 95% CI: 0.70-0.92, P=0.001). Notably, compared to patients scoring ≥6, those scoring 0-3 experienced a 66% increased risk of all-cause mortality (HR 1.66, 95% CI: 1.18-2.34, P=0.004) and a striking 2.76-fold increased risk of cardiovascular mortality (HR 2.76, 95% CI: 1.48-5.17, P=0.001). Conclusion A higher DI-GM is significantly associated with a lower prevalence of advanced CKM syndrome and robustly predicts reduced all-cause and cardiovascular mortality. The DI-GM serves as a valuable clinical tool for risk stratification, highlighting gut microbiota-targeted dietary intervention as a highly promising strategy in the comprehensive management of CKM progression.Figure1Figure2