Association of malnutrition with prognosis in patients with acute myocardial infarction undergoing percutaneous coronary intervention and standard modifiable cardiovascular risk factors

The Nutritional Risk Index (NRI) is a validated clinical instrument for evaluating nutritional status and predicting prognosis across a range of chronic diseases. This study aimed to assess the relationship between the NRI, standard modifiable cardiovascular risk factors (SMuRFs), and long-term clinical outcomes in patients with acute myocardial infarction (AMI). This study enrolled 3811 patients with a confirmed diagnosis of AMI. Nutritional status was evaluated using the NRI, a composite measure incorporating serum albumin levels and body weight. Participants were stratified into four groups based on NRI and SMuRF status. The clinical outcomes included all-cause mortality, cardiovascular death (CV death), non-fatal stroke, and a composite endpoint of revascularization, reinfarction, or cardiac rehospitalization. Among this population, 4.2% were classified as absence of SMuRFs (SMuRF-less), and 28.2% were identified as malnourished during the study period. Patients with ≥ 1 SMuRF and malnutrition exhibited a significantly increased adjusted mortality risk. Using the ≥ 1 SMuRF nourished group as the reference, the ≥ 1 SMuRF malnourished group showed elevated risks for all-cause death [adjusted HR (95% CI): 1.66 (1.31–2.11), P < 0.001], and CV death [adjusted HR (95% CI): 1.41 (1.01–1.97), P < 0.05]. The SMuRF-less malnourished subgroup demonstrated a higher crude event rate, while the association did not retain statistical significance after multivariable adjustment, likely attributable to the limited sample size of this subgroup. In the age-stratified analysis, the association remained statistically significant in both the elderly (> 65 years: adjusted HR, 1.85, 95% CI, 1.41–2.44) and non-elderly (≤ 65 years: adjusted HR, 1.92, 95% CI, 1.18–3.10) subgroups. The association was statistically significant in males (adjusted HR, 1.86, 95% CI, 1.38–2.49). In contrast, no significant association was observed in females (adjusted HR, 1.29, 95% CI, 0.84–1.98). Nutritional assessment using the NRI is valuable for long-term management and risk stratification in patients with coronary heart disease. In the SMuRF-less subgroup, a trend toward higher mortality was observed. However, this finding did not reach statistical significance and therefore requires validation in larger prospective cohorts. Accordingly, claims of an independent risk increase in this subgroup are premature. Nevertheless, the NRI shows promise as a practical early screening tool to identify high-risk individuals who may benefit from closer nutritional monitoring and who could be prioritized in future interventional studies.