Low serum creatinine as a prognostic marker in advanced cancer

Objectives To evaluate whether low serum creatinine levels are associated with poor outcomes in patients with advanced cancer. Methods This is a secondary analysis of a prospective cohort study. Patients were divided into three groups according to their baseline serum creatinine levels. We performed time-to-event analyses using the Kaplan-Meier method and log-rank tests, and by conducting univariate and multivariate Cox regression analyses. Results 809 males were divided: male-low group (n=192), male-normal group (n=403) and male-high group (n=214). 808 females were divided: female-low group (n=239), female-normal group (n=389) and female-high group (n=180). Significant differences were observed in survival rates between the high and normal groups in the males and females (both log-rank p<0.001). Significantly higher risks of mortality were observed in the Cox proportional hazard model for the high group than for the normal group in both sexes (adjusted HR 1.292, 95% CI 1.082 to 1.542; adjusted HR 1.316, 95% CI 1.094 to 1.583, respectively). High serum creatinine was associated with shorter survival than normal creatinine, while low serum creatinine was not. Conclusions Low serum creatinine levels did not have prognostic abilities in this population.