Early prediction of the failure of methotrexate treatment by Days 1–4 serum β-hCG change and 48-hour pre-treatment increment inβ-hCG

Abstract

To determine whether the change of serum β-hCG levels between Days 1 and 4 and 48-h pre-treatment increment in β-hCG can early predict treatment failure of single-dose methotrexate (MTX) in tubal ectopic pregnancies (EP), a retrospective study of 1120 ectopic pregnancies treated with a regimen of a single dose of MTX was conducted in the Department of Obstetrics and Gynaecology, Shanghai First Maternity and Infant Hospital. Treatment failure was defined by an obligation to proceed to surgery or have an additional doses of methotrexate.1350 files were reviewed, with 1120 included for final analysis .64% (722/1120) had β-hCG levels increase on Day 4 after MTX treatment, while 36% (398/1120) had β-hCG levels fall. In this cohort, the treatment failure rate with a single dose of MTX was 15.7% (113/722), and the significant features in the logistic regression model of diagnosing the results of MTX treatment were the ratio of Day 1 to Day 48-h pre-treatment β-hCG values (Odds Ratio (OR) 1.221, 95% Confidence interval (CI) 1.159–1.294), the ratio of Day 4 to Day 1 β-hCG serum values (OR 1.098, 95% CI 1.014–1.226), and β-hCG values on Day 1 (OR 1.070, 95% CI 1.016–1.156). The decision tree model was developed by using increment of β-hCG in 48 h before treatment > =19%, the ratio of Day 4 to Day 1 β-hCG serum values > =36%, and β-hCG values on Day 1> =728 mIU/L to predict the failure of MTX treatment. The diagnostic accuracy, sensitivity and specificity in the test group were 97.22%, 100%, and 96.9%, respectively.

IMPACT STATEMENT

• What is already known on this subject? A decrease of 15% β-hCG levels between Days 4 and 7 is a common protocol for predicting the success of a single-dose methotrexate therapy of an ectopic pregnancy.

• What do the results of this study add? This clinical study offers the cut-off values points for prediction of single-dose methotrexate treatment failure.

• What are the implications of these findings for clinical practice and/or further research? We identified the importance of β-hCG increase between Days 1 and 4 and β-hCG increment in 48 h pre-treatment for predicting the failure of single-dose methotrexate therapy. It can be used to aid the clinician to optimise the selection of the most appropriate treatment methods during a follow-up evaluation after MTX treatment.

Keywords:

• Ectopic pregnancy
• methotrexate β-hCG
• decision tree model

Acknowledgments

The authors would like to acknowledge the assistance of research nurses in the collection of the data analyzed in this study. We also thank members of the Department of Shanghai First Maternity and Infant Hospital for providing the infrastructure for the collection of some of the data included in this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.