Changes in Day 4 and day 0 Neutrophil-lymphocytes ratio in predicting single-dose methotrexate treatment failure for ectopic pregnancies

Abstract Purpose We aimed to evaluate changes in neutrophil/lymphocyte ratio between the day 4 and day 0 of ectopic pregnancy (EP) patients treated with single-dose methotrexate (MTX). And to further investigate whether the NLR change is an indicator for MTX treatment outcome. Methods Totally 406 patients underwent single-dose MTX therapy for EP at Shanghai First Maternity and Infant Hospital from 2013/01/10 to 2019/09/30 were studied. A multivariate model was structured to predict the treatment outcome. Results Finally, 281 patients were in the successful treatment group, and their NLR at day 4 dropped 25% when compared with day 0. The success rate was significantly declined when the NLR decreased less than 23% (74.8% vs 58.5%, p = 0.004). Multivariate regression analysis revealed that day 4/day 0 NLR reduced less than 23% (OR:2.09, 95%CI:[1.27–3.44]); hCG decreased no more than 15% (OR:3.17,95% CI: [1.62–6.34] and increased over 15% on day 4 (OR:5.47, 95% CI: [3.05–10.22]) were independent risk factors for single-dose MTX treatment failure. Our final predictive model had a sensitivity of 0.768 and specificity of 0.569 when we chose 3 as the cut-off value. The area under the receiver operating characteristic curve was 0.712. Patients with a predictive score of ≥ 3 are more likely to fail in a single-dose MTX therapy. Conclusion In this study, we concluded that NLR decreased less than 23% on day 4 compared with day 0, a plateau or increased serum hCG on day 4 and hCG value over1000 mIU/ml at day 0 were predictors of single-dose MTX treatment failure.