Red blood cell distribution width-to-albumin ratio is associated with all-cause mortality in cancer patients

Background Cancer causes a serious health burden on patients worldwide. Chronic low-level inflammation plays a key role in tumorigenesis and prognosis. However, the role of the red blood cell distribution width (RDW)-to-albumin (RA) ratio in cancer mortality remains unclear. Methods In this retrospective cohort study, we collected clinical information from cancer patients from the Medical Information Mart for Intensive Care III (MIMIC-III) version 1.4 database and then calculated RA by dividing RDW by albumin concentration. The primary outcome was 30 days mortality, while secondary outcomes were 90 days and 1 year mortality. Next, we adopted Cox regression models to calculate hazard ratios (HR) together with 95% confidence intervals (CI) for all-cause mortalities associated with the RA ratio. Results For 30 days mortality, the HR (95% CI) for the high RA ratio (>= 5.51) was 2.17 [95CI% (1.87-2.51); p = <0.0001], compared with the low RA ratio (<5.51). In Model 2, we adjusted sex and age and obtained HR (95% CI) of 2.17 [95CI% (1.87-2.52); p = <0.0001] for the high RA ratio (>= 5.51) group, compared to that in the low RA ratio (<5.51). In Model 3, adjusting for age, sex, anion gap, hematocrit, white blood cell count, congestive heart failure, SOFA, liver disease, and renal failure resulted in HR (95% CI) of 1.74 [95CI% (1.48-2.04); p = <0.0001] for the high RA ratio (>= 5.51) relative to the low RA ratio (<5.51). We also analyzed common diseases in cancer patients but found no significant association. Conclusion To the best of our knowledge, this is the first study demonstrating that increased RA ratio is independently associated with increased all-cause mortality in cancer patients.