Potential of the prognostic nutritional index to determine the risk factor for severe infection in elderly patients with rheumatoid arthritis

To investigate the influence of nutritional status on severe infection complications in patients with rheumatoid arthritis (RA).This retrospective cohort study on 2108 patients with RA evaluated the prognostic nutritional index (PNI) as an index of nutritional status. Patients were classified into the high or low PNI group according to the cutoff PNI value (45.0). Based on propensity score matching analysis, 360 patients in each group were selected for comparing the incidence of serious infection, clinical findings, and PNI scores.The incidence of infection was significantly higher in the low PNI group than in the high PNI group (p < 0.001). The occurrence rate of infectious complication at 104 weeks was significantly higher in the low PNI (<45.0) group than in the high PNI group (p < 0.001). The incidence of infection was particularly high in elderly patients (≥65 years) with a low PNI, but the incidence in elderly patients with a high PNI was similar to that in nonelderly patients with a high PNI.Patients with RA and malnutrition had a higher incidence of severe infection; thus, evaluating and managing nutritional status is necessary for the appropriate and safe treatment of elderly patients with RA.