Clinical relevance of neutrophil/lymphocyte ratio combined with APACHEII for prognosis of severe heatstroke

Abstract

We evaluated clinical implication of neutrophil-lymphocyte ratio (NLR) for severe heatstroke and predictive value of combined acute physiology and chronic health evaluation (APACHEII) score for prognosis of severe heatstroke. Retrospectively, we studied 185 individuals that have been admitted at emergency department for severe heatstroke. On the basis of their prognosis, we sorted the patients into two categories, namely non-survival (n = 43) and survival groups (n = 142). The primary outcome was 30-day mortality. A considerably higher NLR was observed among the non-survivors compared to survivors (P < 0.05). After correction for confounders, statistical analysis using multi-variable Cox regression indicated NLR as an independent risk factor for patient death (HR = 1.167, 95%CI = 1.110–1.226, P < 0.001). Through receiver-operating characteristics (ROC) curve, we estimated area-under the curve (AUC) of NLR to be 0.7720 (95% CI [0.6953, 0.8488]). Also, transformation of NLR into a profile type analysis showed that the marker remained a risk factor for death, which showed trend variation (P for trend <0.001). Subgroup forest plot analysis showed robustness in the predictive ability of NLR after exclusion of confounders. Besides, we demonstrated through Kaplan-Meier (KM) survival analysis curve that high risk NLR mortality substantially exceeded low risk NLR. The combined prediction of NLR and APACHEII achieved higher efficacy than NLR and APACHEII alone (AUC = 0.880, 95% CI [0.8280, 0.9290]). Additionally, Delong test indicated that the combined prediction demonstrated a significantly greater ROC than NLR and APACHEII alone, while DCA showed a considerably higher clinical net benefit rate. Increased NLR is a high risk factor and has predictive value for death in individuals with severe heatstroke. Suggestively, combination of NLR and APACHEII have greater predictive value.