Prognostic nutritional index as indicator of immune nutritional status of patients with COVID-19

Purpose: This study aimed to investigate the effect of the nutritional status, as assessed by the prognostic nutritional index (PNI) on the disease prognosis of patients with COVID-19. Methods: This retrospective study included 282 patients with COVID-19. The PNI score of all patients, 147 of whom were male, with a mean age of 56.4±15.3 years, was calculated. According to the PNI score, the patients with normal and mild malnutrition constituted group-1 (n=159) and the patients with moderate-to-severe and serious malnutrition constituted group-2 (n=123). Results: The PNI score was correlated with age (r=-0.146, p=0.014); oxygen saturation (r=0.190, p=0.001); heart rate (r=-0.117, p=0.05); hospitalization duration (r=-0.266, p<0.001); white blood cells (r=0.156, p=0.009); hemoglobin (r=0.307, p<0.001); C-reactive protein (CRP) (r=-0.346, p<0.001); creatinine (r=-0.184, p=0.002); D-dimer (r=-0.304, p<0.001); ferritin (r=-0.283, p<0.001); procalcitonin (r=-0.287, p<0.001); the confusion, urea, respiratory rate, blood pressure, and age ≥65 years score (r=-0.217, p<0.001); and the quick sequential organ failure assessment score (r=-0.261, p<0.001) in patients with COVID-19. Mortality was significantly higher in Group 2 (p<0.001). Survival was significantly higher if PNI score was >41.2 (p<0.001, sensitivity: 78.7% and specificity: 84.2%). In multivariate regression analysis, among various other parameters, only PNI score and oxygen saturation had a significant effect on the disease course (p=0.02 and p=0.045, respectively). Conclusion: PNI, calculated from the serum albumin concentration and total lymphocyte count, is a simple and objective indicator that assesses the immune nutritional status of patients with COVID-19. The presence of malnutrition has a high predictive value in predicting the severity of COVID-19. Our data suggest that the PNI might be useful for risk stratification of patients with COVID-19 in clinical practice.