Day 1 to day 4 serum hCG change in predicting single-dose methotrexate treatment failure for tubal ectopic pregnancies

Comparison of the success rates of a single dose and an additional dose of methotrexate on the 4th day in patients whose β-hCG values do not fall after a single dose of methotrexate (Day 0-4)

INTRODUCTION

This study's aim is to investigate whether the rise in β-hCG levels between days 0 and 4 in patients with tubal ectopic pregnancy who have received a single dose of methotrexate has prognostic value in treatment success, and to investigate whether administering a second dose on day 4 enhances treatment success.

MATERIAL AND METHODS

Patients diagnosed with ectopic pregnancy and experiencing an increase in β- hCG levels on day 4 after initiation of methotrexate treatment were included in our study. Patients treated with a single dose Methotrexate (MTX) protocol until December 2019 were retrospectively screened from January 2018 to December 2019. Patients receiving a second dose on day 4 until September 2021 were prospectively enrolled from January 2020 to September 2021. A decrease of over 15 % in the β-hCG value after the 4th dose was considered as treatment success.

RESULTS

Treatment success rates were compared between these two groups. 115 patients with ectopic pregnancy were included in the study. A single dose methotrexate protocol was applied in 67 of the patients (Group 1), while an additional dose methotrexate was applied in 48 (Group 2). The treatment was successful in 40 patients (59.7 %) in Group 1 and in 39 patients (81.3 %) in Group 2. The success rate of the treatment was significantly higher in patients who received an additional dose methotrexate protocol (p = 0.014).

DISCUSSION

This study shows that; it is possible to increase success rates by applying an additional MTX dose on the 4th day in cases with an increase in β-hCG on the 4th day.

Predictive value of serum βHCG level in ectopic pregnancy: A cross sectional study

Background and Aims

Ectopic pregnancy (EP) is a potentially life-threatening emergency. We investigate the predictive value of serum βHCG level and it's changes from the baseline to the 4th and 7th days after single dose (SD) methotrexate (MTX) treatment in successful treatment of tubal EP. It is important for early diagnosis of EP.

Methods

In this cross-sectional study, 690 women with tubal EP and under treatment with SD MTX were evaluated. Successful and failed groups were analyzed on the baseline, 4th and 7th days of MTX treatment. Data were analyzed using SPSS22 software. All p values of less than 0/05 were considered satistically significant.

Results

SD MTX treatment was successful in 584 (84.7%) patients. The mean baseline ßHCG value was 882.35 ± 430.76 in the successful group and 1083.99 ± 1080.25 in the failed group. There was a 19.53% decrease in ßHCG values between the baseline and 4th days in the successful group and a 12.94% increase in the failed group (p < 0.001). On days baseline, 4 and 7; receiver operating characteristic curve analysis's value was 504.5, 429, 279 for cut off; 58%, 73%, 81% for sensitivity and 51%, 52%, 55% for specificity, respectively.

Conclusion

A decrease in the ßHCG value and/or a cut-off decrease of 59.9% on the baseline, 4th day and 81.6% between the baseline and 7th days, can predict the successful treatment of tubal EP with SD MTX.

Early (Days 1-4) post-treatment serum hCG level changes predict single-dose methotrexate treatment success in tubal ectopic pregnancy

STUDY QUESTION

What is the capacity of the change between Day 1 and Day 4 post-treatment serum human chorionic gonadotropin (hCG) levels for predicting single-dose methotrexate treatment success in tubal ectopic pregnancy?

SUMMARY ANSWER

Any fall in Days 1-4 serum hCG signified an 85% (95% CI 76.8-90.6) likelihood of treatment success for women with tubal ectopic pregnancy (initial hCG of ≥1000 and ≤5000 IU/l) managed with single-dose methotrexate.

WHAT IS KNOWN ALREADY

For those with tubal ectopic pregnancy managed by single-dose methotrexate, current guidelines advocate intervention if Days 4-7 hCG fails to fall by >15%. The trajectory of hCG over Days 1-4 has been proposed as an early indicator that predicts treatment success, allowing early reassurance for women. However, almost all prior studies of Days 1-4 hCG changes have been retrospective.

STUDY DESIGN, SIZE, DURATION

This was a prospective cohort study of women with tubal ectopic pregnancy (pre-treatment hCG of ≥1000 and ≤5000 IU/l) managed with single-dose methotrexate. The data were derived from a UK multicentre randomized controlled trial of methotrexate and gefitinib versus methotrexate and placebo for treatment of tubal ectopic pregnancy (GEM3). For this analysis, we include data from both treatment arms.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were categorized according to single-dose methotrexate treatment success or failure. Treatment success for this analysis was defined as complete and uneventful resolution of tubal ectopic pregnancy to serum hCG <30 IU/l following single-dose methotrexate treatment without additional treatment. Patient characteristics of the treatment success and failure groups were compared. Changes in Days 1-4, 1-7, and 4-7 serum hCG were evaluated as predictors of treatment success through receiver operating characteristic curve analysis. Test performance characteristics were calculated for percentage change ranges and thresholds including optimal classification thresholds.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 322 women with tubal ectopic pregnancy were treated with single-dose methotrexate. The overall single-dose methotrexate treatment success rate was 59% (n = 189/322). For any fall in serum hCG on Days 1-4, likelihood ratios were >3, while for any fall of serum hCG >20% on Days 1-7, likelihood ratios reached 5. Any rise of serum hCG on Days 1-7 and 4-7 strongly reduced the chance of success. Any fall in Days 1-4 hCG predicted single-dose methotrexate treatment success with a sensitivity of 58% and specificity 84%, resulting in positive and negative predictive values of 85% and 57%, respectively. Any rise in Days 1-4 serum hCG <18% was identified as an optimal test threshold that predicted treatment success with 79% sensitivity and 74% specificity, resulting in 82% positive predictive value and 69% negative predictive value.

LIMITATIONS, REASONS FOR CAUTION

Our findings may be limited by intervention bias resulting from existing guidelines which influences evaluation of hCG changes reliant on Day 7 serum hCG levels.

WIDER IMPLICATIONS OF THE FINDINGS

Examining a large prospective cohort, we show the value of Days 1-4 serum hCG changes in predicting single-dose methotrexate treatment success in tubal ectopic pregnancy. We recommend that clinicians provide early reassurance to women who have a fall or only a modest (<18%) rise in Days 1-4 serum hCG levels, that their treatment will likely be effective.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by funding from the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research partnership (grant reference number 14/150/03). A.W.H. has received honoraria for consultancy for Ferring, Roche, Nordic Pharma and AbbVie. W.C.D. has received honoraria from Merck and Guerbet and research funding from Galvani Biosciences. L.H.R.W. has received research funding from Roche Diagnostics. B.W.M. is supported by a NHMRC Investigator grant (GNT1176437). B.W.M. also reports consultancy for ObsEva and Merck and travel support from Merck. The other authors declare no competing interests.

TRIAL REGISTRATION NUMBER

This study is a secondary analysis of the GEM3 trial (ISRCTN Registry ISRCTN67795930).