Malnutrition-Inflammation Status as a Predictor of Outcomes in Hemodialysis Patients: A Prospective Cohort Study

Background: Malnutrition and inflammation are highly prevalent in hemodialysis patients and are strongly linked to adverse outcomes. While traditional nutritional assessments provide valuable insights, the Malnutrition-Inflammation Score (MIS) may offer superior prognostic ability compared with conventional measures. Methods: This prospective observational cohort included 416 adult patients undergoing thrice-weekly hemodialysis at three centers in Istanbul, Türkiye. Nutritional status was assessed using the Subjective Global Assessment (SGA) and MIS. Laboratory parameters, including serum albumin, C-reactive protein (CRP), and hemoglobin, were measured. Patients were followed for 12 months to evaluate all-cause mortality and hospitalizations. Survival was analyzed with Kaplan–Meier curves, while Cox regression identified independent predictors. Results: Malnutrition was highly prevalent, with 56.2% of patients classified as moderately or severely malnourished by SGA and 23.3% exhibiting MIS > 12. Malnourished patients had significantly lower albumin (3.12 vs. 3.82 g/dL), higher CRP (15.2 vs. 8.1 mg/L), and lower hemoglobin (9.8 vs. 11.0 g/dL) compared with well-nourished patients (p < 0.001). One-year mortality was 36.4% in SGA-C and 37.1% in MIS > 12, versus 6.6% and 5.5% in well-nourished/low-MIS patients. MIS demonstrated superior prognostic accuracy for mortality (AUC = 0.79) compared with SGA (AUC = 0.75). Multivariate Cox analysis identified MIS > 12 (HR = 2.35), serum albumin < 3.5 g/dL (HR = 1.80), CRP > 10 mg/L (HR = 1.50), age ≥ 60 years (HR = 1.45), and diabetes (HR = 1.25) as independent predictors of mortality. Mediation analysis showed that hypoalbuminemia and elevated CRP explained nearly 80% of the MIS–mortality association. Conclusions: MIS provides robust prognostic information, outperforming SGA in predicting mortality and hospitalization. Malnutrition and inflammation synergistically drive poor outcomes, with albumin and CRP mediating much of the risk. Integrating MIS into routine practice and implementing early nutritional interventions may improve survival in this vulnerable population.