Association of Dietary Inflammatory Index (DII) with cardiovascular and all-cause mortality in patients with Cardiovascular-Kidney-Metabolic (CKM) syndrome: a prospective cohort study.

BACKGROUND

Cardiovascular-kidney-metabolic syndrome (CKM) is closely associated with obesity, diabetes, chronic kidney disease (CKD), and cardiovascular disease (CVD). Although the dietary inflammatory index (DII) reflects the inflammatory potential of diet, the relationship between CKM and DII, as well as the potential mediators, remains unclear.

METHODS

This prospective cohort study included adults with complete dietary data from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. DII was ascertained using the 24-hour recall method. Cox models and cubic spline analyses assessed mortality risk, while the mediating role of insulin resistance-related indicators was further investigated by causal mediation analysis.

RESULTS

As of December 31, 2019, a total of 2,505 (13.4%) all-cause deaths and 777 (4.1%) cardiovascular deaths were documented in 18,746 adults over a median follow-up of approximately 8 years. Highest DII tertile showed increased all-cause mortality (HR = 1.24, 95%CI:1.11-1.37) and cardiovascular mortality (HR = 1.22, 95%CI:1.01-1.48) versus lowest tertile. RCS analysis showed that mortality risk increased linearly with increasing DII (all-cause mortality: P for overall: <0.001; cardiovascular mortality: P for overall: <0.135). The time-dependent curves show the long-term predictive performance of DII. In addition, TyG-WC and TyG-WHtR mediated 4.69% and 4.18% of all-cause mortality and 13.13% and 13.96% of cardiovascular mortality (both P < 0.05) in DII and CKM patients, respectively.

CONCLUSIONS

Elevated DII was strongly associated with an elevated risk of death in patients with CKM. In addition, the TyG index and its combined indicator of abdominal obesity partially mediated the association between DII and mortality risk in CKM.