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.