Association between serum C-reactive protein-to-albumin ratio and the prognosis of patients with multiple myeloma

Background: The aim of this study was to investigate the association between serum C-reactive protein-to-albumin ratio (CAR) and the prognosis of multiple myeloma (MM). Methods: In this single-center retrospective cohort study, a total of 321 patients diagnosed with MM were enrolled between February 2008 and December 2020. All patients were divided into two groups according to the optimal cutoff value of CAR. Cox proportional hazard regression model and receiver operating characteristic (ROC) curve analysis were conducted to assess the prognostic predictive value of CAR. Results: Higher CAR was significantly associated with shorter overall survival (OS), cause-specific survival (CSS), and progression-free survival (PFS) (HR = 1.864, 95%CI = 1.287–2.699, P < 0.001 for OS; HR = 1.916, 95%CI = 1.052–2.546, P < 0.001 for CSS; HR = 1.748, 95%CI = 1.291–2.367, P < 0.001 for PFS). The significance remained after multivariable logistic regression analysis (HR = 1.628, 95%CI = 1.066–2.485, P = 0.024 for OS; HR = 1.636, 95%CI = 1.052–2.546, P = 0.029 for CSS; HR = 1.666, 95%CI = 1.185–2.343, P = 0.003 for PFS). CAR demonstrated significantly higher predictive power compared to both albumin ( P < 0.05) and C-reactive protein ( P < 0.05) in terms of OS, CSS, and PFS. The composite variable exhibited the highest predictive value ( P < 0.001). Conclusions: Higher CAR was found to be an independent predictor for the poor prognosis of MM.