Association between the Prognostic Nutritional Index and the Occurrence of Immune-Related Adverse Events

Immune-related adverse events (irAEs) affect all organs and are associated with various symptoms. The identification of biomarkers that can predict irAEs may be particularly clinically useful. This study aimed to investigate whether the prognostic nutritional index (PNI) before the initiation of immune checkpoint inhibitor (ICI) treatment can predict the occurrence of irAEs. We conducted a survey of 111 patients with cancer who were receiving ICI fixed-dose monotherapy at Saga University Hospital from the time each ICI became available until January 2020. We compared the PNI between the patients with and without irAE expression, established a cutoff value for PNI associated with the development of irAEs, and investigated the incidence of irAEs and progression-free survival (PFS) in groups divided by the cutoff value. Patients with irAEs had significantly higher PNI than did those without, and there was a significant association between PNI and irAEs after adjusting for potential factors (odds ratio, 1.12; 95% confidence interval, 1.03-1.21). In addition, PNI ≥44.2 was associated with a significantly higher incidence of irAEs (75.0% vs. 35.2%, p = 0.0001) and significantly longer PFS than PNI <44.2 (p = 0.025). In conclusion, pretreatment PNI may be associated with the risk of developing irAEs in patients with advanced recurrent solid tumors. When the PNI is ≥44.2, patient management is important for avoiding serious AEs because while the treatment may be effective, the occurrence of irAEs is a concern.