Diet–Gut Microbiota Interaction Index and Heart Failure Risk in Diabetes and Prediabetes: Evidence from NHANES 2007–2018

AIMS: Diabetes and prediabetes markedly increase the risk of heart failure (HF), but the role of diet-gut microbiota interactions remains unclear. This study examined the association between the Dietary Index for Gut Microbiota (DI-GM) and HF risk among individuals with diabetes or prediabetes. METHODS: Data were obtained from 15 219 adults with diabetes or prediabetes in the US National Health and Nutrition Examination Survey (NHANES) 2007-2018. DI-GM scores were calculated from two 24-h dietary recalls covering 14 food groups linked to gut microbiota. Associations between DI-GM and prevalent HF were estimated using weighted logistic regression and restricted cubic spline models, adjusting for demographic, lifestyle, and metabolic factors. RESULTS: Participants had a mean age of 59.7 ± 13.2 years, and 48.3% were women. Higher DI-GM scores were independently associated with lower HF risk (adjusted odds ratio [OR] per 1-point increase = 0.93, 95% confidence interval [CI] 0.89-0.98; p = 0.005). Compared with scores 0-3, DI-GM ≥ 6 was linked to 27% lower HF risk (OR = 0.73, 95% CI 0.58-0.92; p = 0.007). The inverse association was stronger in prediabetes (OR = 0.89, 95% CI 0.82-0.96; p = 0.004) but not significant in diabetes. CONCLUSIONS: Higher DI-GM was associated with lower HF risk, particularly in prediabetes. Microbiota-related dietary patterns may play a role in HF prevention among metabolically at-risk populations.