Prognostic value of serum albumin-creatinine ratio as a biomarker in patients treated with immune checkpoint inhibitors

Albumin and creatinine are considered important for understanding patient response to immune checkpoint inhibitors (ICIs). However, numerous confounding factors complicate the interpretation of albumin and creatinine alone in clinical practice. This study aims to assess the correlation between survival outcomes and serum-albumin creatinine ratio (sACR) in patients treated with ICIs. This study was conducted on individuals who received at least three doses of ICI between 2018 and 2023. Patients were divided into two groups, sACR-High and sACR-Low, based on the median level. The relationship between sACR and survival outcomes was analyzed using a cox regression model. The relationship between sACR and early progression, late progression, and long-term benefit was analyzed using a logistic regression model. Patients with lower sACR had decreased overall survival (OS) (HR: 1.42, 95% CI 1.07-1.89, p = 0.014) and progression-free survival (PFS) (HR: 1.34, 95% CI 1.08-1.66, p = 0.009). sACR was associated with early progression (HR: 1.86, 95% CI, 1.14-3.01, p = 0.012), late progression (HR: 2.06, 95 % CI 1.0-4.24, p = 0.050), and long-term benefit of ICIs (HR: 1.72, 95% CI 1.002-2.93, p = 0.049). Our study demonstrated that sACR could serve as an independent predictor of OS, PFS, early progression, late progression, and long-term benefit in patients treated with ICIs.