Prognostic Value of the Geriatric Nutritional Risk Index for Long-Term All-Cause Mortality in Older Patients with Non-ST-Segment Elevation Myocardial Infarction

BACKGROUND & AIMS Malnutrition is associated with poor outcomes in various diseases. This study aimed to evaluate the independent prognostic value of the Geriatric Nutritional Risk Index (GNRI) for long-term all-cause mortality in older patients with non-ST-segment elevation myocardial infarction (NSTEMI), and to further explore its joint effects with obesity, inflammation, hypercoagulability, and cardiac dysfunction, as well as potential underlying pathways. METHODS This single-center cohort study consecutively enrolled 1686 patients aged ≥60 years hospitalized with NSTEMI at Tianjin Chest Hospital between March 2016 and December 2020. According to admission GNRI, patients were categorized into nutritional risk (GNRI ≤98) and no nutritional risk (GNRI >98) groups. The endpoint was all-cause mortality. Restricted cubic spline analyses and Cox proportional hazards models were used to assess the dose-response relationship and independent association between GNRI and mortality. Joint and mediation analyses were further performed to evaluate combined prognostic effects and explore potential mediating pathways. RESULTS During a median follow-up of 5.36 years (interquartile range, 4.17-6.57 years), 249 (14.8%) deaths occurred. GNRI showed a near-linear inverse association with mortality in both the overall NSTEMI cohort and the diabetes mellitus and metabolic syndrome subgroups. Each 1-SD decrease in GNRI was associated with a 24% higher mortality risk (HR 1.24, 95% CI 1.10-1.41; P < 0.001). Compared with GNRI >98, GNRI ≤98 was independently associated with increased all-cause mortality after full adjustment (HR 1.45, 95% CI 1.11-1.88; P = 0.006). Joint analyses revealed that all-cause mortality risk further increased when GNRI ≤98 coexisted with BMI ≥28 kg/m2, hs-CRP >5 mg/L, D-dimer >0.5 mg/L, or NT-proBNP ≥945 pg/mL, with the highest risk observed in patients with concomitant elevation of NT-proBNP (HR 2.23, 95% CI 1.47-3.39; P < 0.001). Furthermore, hs-CRP and NT-proBNP mediated 8.6% and 12.4% of the association between GNRI and mortality, respectively. CONCLUSIONS Poor nutritional status independently increases the risk of long-term all-cause mortality in older patients with NSTEMI. Low GNRI combined with obesity, high inflammation, hypercoagulability, and cardiac dysfunction further exacerbates this risk, highlighting their combined value in identifying individuals at extremely high risk of mortality.