We aimed to investigate the role of neutrophil to lymphocyte ratio (NLR) and the C-Reactive Protein/Albumin Ratio (CAR), which are obtained from the first laboratory values of the elderly patients at admission to the emergency department (ED), in predicting in-hospital mortality.

This retrospective observational study includes the patients aged 65 and above who applied to the emergency department for two months. The patients' neutrophil, lymphocyte, C-reactive protein (CRP), albumin, NLR and CAR values were recorded. Statistical analysis of NLR and CAR values was performed according to in-hospital mortality and ED outcome.

784 patients were included in the statistical analysis of the study. Increased NLR (8.82 (4.16–16.63), 4.76 (2.62–8.56), p˂0.001) and increased CAR (21.39 (6.02–55.07), 4.82 (1.17–17.03), p < 0.001) values were found to be statistically significant in the group with mortality compared to the group without mortality. Increased NLR (AUC: 0.642) and increased CAR (AUC: 0.723) were a predictor of in-hospital mortality. It was found that in-hospital mortality risk in patients with concurrent high NLR and CAR values (CAR˃12.3, NLR˃7.1) was 9.87 times more than the patients with concurrent low NLR and CAR values (CAR<12.3, NLR < 7.1). NLR and CAR values of the patients hospitalized in intensive care and service (NLR 7.21 (4.07–13.36), 5.77 (3.45–11.22); CAR 12.65 (2.79–36.8), 9.56 (1.74–33.97)) were found to be statistically significantly higher than those who were discharged (NLR 3.64 (2.26–7.02); CAR 2.88 (0.9–10.59)).

According to our results, the concurrent high levels of NLR and CAR values were found to be more effective in predicting in-hospital mortality compared to a separate evaluation.