The nonlinear correlation of neutrophil-lymphocyte ratio on 1-year mortality risk in patients with severe acute heart failure

Abstract

Background: This retrospective cohort study was designed to examine the relationship between the neutrophil-lymphocyte ratio (NLR) and the 1-year risk of death in patients with acute heart failure (AHF) in the intensive care unit (ICU).

Methods: We retrospectively analyzed 1,176 patients with AHF from the MIMIC-IV database. Cox regression was used to evaluate the relationship between NLR and 1-year mortality risk after adjusting for covariates. Nonlinear associations and optimal NLR cutoff values were determined using restricted cubic splines. Propensity score matching was used to eliminate imbalances in the baseline confounders. Kaplan-Meier survival analysis further confirmed the correctness of the threshold. The ROC was used to evaluate the diagnostic accuracy of the NLR for long-term outcomes. Subgroup analyses were performed to assess the generality of NLR in specific populations.

Results: The mortality rate was lowest in the lower tertile NLR group (< 5.43) and highest in the upper tertile group (> 13.53, P for trend < 0.001). NLR showed a nonlinear correlation with mortality (P for Non-linearity = 0.0075), with the risk increasing significantly when NLR exceeded 11.11. The AUC of NLR for predicting 1-year mortality was 0.579 (95%CI 0.542-0.617). The NLR was not significantly different from long-term outcomes in most groups, but the association was stronger in patients with AHF who did not have sepsis.

Conclusion: Elevated NLR, a marker of heightened systemic inflammation, was associated with a higher risk of 1-year mortality in ICU patients with AHF.

Clinical trial number: Not applicable.

Keywords: Acute heart failure; Intensive care unit; MIMIC IV; Neutrophil lymphocyte ratio.

Fig. 1

Flow chart of patient eventually selection included in this study. AHF: Acute heart failure; ICU: Intensive care unit; NLR: Neutrophil lymphocyte ratio

Fig. 2

The mortality rate during follow-up was compared between different tertiles. T1: The lowest third of the data; T2: The middle third of the data; T3: The highest third of the data; TNLR: Tertile of neutrophil lymphocyte ratio

Fig. 3

The nonlinear relationship between NLR and death risk. NLR: Neutrophil lymphocyte ratio; HR: Hazard ratio; CI: Confidence interval

Fig. 4

(A). The kernel density plot indicates that the propensity scores of the two groups were best matched after adjustment. (B). Point plots indicate the matches for each patient between the two groups as well as those that were not matched. (C). The love point shows the situation of each variable before and after matching, after matching each variable has basically reached the equilibrium state. Survival analysis ROC curve. ROC: Receiver operating characteristic

Fig. 5

The curves of Kaplan–Meier’s survival analysis. (A). The curves of Kaplan–Meier’s survival analysis in the unmatched cohort. (B). The curves of Kaplan–Meier’s survival analysis in the matched cohort

Fig. 6

Receiver operating curve for the MIMIC cohort

Fig. 7

The forest plot of subgroup analysis