Predictive value of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for 28-day death in patients treated with extracorporeal membrane oxygenation

Abstract

The study aimed to evaluate the predictive value of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) for 28-day mortality in patients treated with extracorporeal membrane oxygenation (ECMO). Patients receiving ECMO treatment were selected from the Department of Intensive Care Medicine of Zhejiang Hospital from January 2019 to February 2022. The moment when patients started receiving ECMO treatment was set as the starting point, and death at 28 days was set as the endpoint. The patients were divided into survivors and deaths. Laboratory tests, such as neutrophil, lymphocyte, and platelet counts, using the peripheral blood of all patients were collected within 24 h after ECMO treatment. NLR and PLR were calculated. The risk factors influencing prognosis were analyzed by logistic regression. The correlation between NLR, PLR, acute physiology, and chronic health score Ⅱ (APACHE Ⅱ) was investigated. Receiver operating characteristic (ROC) curve analysis was used to analyze the value of NLR and PLR in predicting the 28-day mortality of patients treated with ECMO. Kaplan-Meier method was used to analyze the cumulative survival of patients at 28 days. The results showed that of 53 patients, 20 survived, and 33 died. The NLR and PLR of the deceased were higher than those of the survivors (NLR: 30.67±14.48 vs. 17.41±7.06;PLR: 303.34±159.23 vs. 191.54±106.03;P<0.001). NLR and PLR were positively correlated with APACHE Ⅱ (r=0.296, r=0.284, P<0.05). ROC curve analysis showed that the area under the curve (AUC) of NLR and PLR to predict the 28 d death of ECMO-treated patients was 0.805 and 0.714, respectively, and the optimal cutoff values of NLR and PLR were 18.93 and 253.0, respectively. The 28-day fatality rate in patients with NLR≥18.93 was higher than that in patients with NLR<18.93 [86.20%(25/29) vs. 33.33%(8/24), χ2=15.625, P<0.01],that in patients with a PLR≥253.0 was higher than that in patients with PLR<253.0 [82.61%(19/23) vs. 46.67%(14/30), χ2=7.158, P<0.01]. Kaplan-Meier survival curve showed that the 28-day cumulative survival rate of NLR≥18.93 was lower than that of NLR<18.93 [9.00 (2.00, 19.50) d vs. 28.00 (10.75, 28.00) d, Z=-3.124, P<0.01], and that of PLR≥253.0 was lower than that of PLR<253.0 [6.00 (2.00, 19.00) d vs. 28.00 (6.25, 28.00) d, Z=-2.673, P<0.01]. Thus, NLR and PLR have good predictive value for 28-day mortality in patients treated with ECMO.