3.1 Baseline data
A total of 238 women with ectopic pregnancies were treated with MTX therapy, and only 213 women were eligible for the final analysis at our institution (25 women underwent surgery before day-4 MTX). The maximum age of the patients was 44 years, the minimum age was 15 years, and the average age was 29.08± 5.29 years. The duration of amenorrhea was 36~62 days, and the average duration was 47.35±6.72 days. After MTX treatment, all patients were divided into two groups, namely, 166 patients in the successful treatment group and 47 patients in the failed treatment group, according to the final treatment outcome. The follow-up duration was 1-6 months.
The overall success rate of MTX therapy was 77.93% (166/213), and 22 patients (13.25%) required a second dose of MTX to achieve complete resolution. There were 47 patients with failed treatment (22.07%) (Fig 1). The baseline data for the successful and failed treatment groups are shown in Table 1. There were no statistically significant differences in the demographic profiles of the groups (Table 1).
3.2 The relationship between β-hCG changes and treatment outcomes
The mean β-hCG levels on day 0, day 4 and day 7 of the successful treatment group and failed treatment group are shown in Table 2. The rank-sum test showed statistically significant differences between the two groups (P<0.001). Regarding cases in which the β-hCG levels on the 4th day decreased, 92.47% (135/146) of the cases were in the successful treatment group. In contrast, in the group in which the day-4 β-hCG levels increased, only 56.27% (31/67) of the cases had successful treatment (P value = 0.000, chi-squared test).
The changes in the β-hCG levels (hCG04) between the initial day and the 4th day were calculated as (HCG4-HCG0)/HCG0. The median HCG04 values of the two groups were -0.30 and 0.53, and the differences between the two groups were statistically significant per the rank-sum test (Z=-7.584, P=0.000<0.001) (Table 2). Negative numbers indicate that the day-4 β-hCG levels decreased, and positive numbers indicate that the day-4 β-hCG levels increased).
3.3 The changes in the β-hCG value between the initial day and the 4th day predicts the outcome of treatment
Based on the ROC curve, the areas under the ROC curve (Figs 1, 2) of the initial β-hCG level and the day-4 β-hCG change were 0.624 (95% CI: 0.534-0.713) and 0.863 (95% CI: 0.805-0.920), respectively. The diagnostic value of the day-4 change was higher than that of the initial β-hCG level. The best cut-off for the initial β-hCG was 3933.78 IU/L, which provided a sensitivity of 78.9% and a specificity of 46.8%. The positive predictive value was 59.73%, and the negative predictive value was 68.92%. The best cut-off for the day-4 β-hCG change was 0.082 (8.2%). This cut-off provided a sensitivity of 88.6% and specificity of 74.5%. The positive predictive value was 77.65%, and the negative predictive value was 86.73%. The various cut-off values of the initial β-hCG and the day-4 β-hCG index are depicted in Tables 3 and 4.
The chi-squared test was used to analyze the difference between the treatment success rate of the group with an initial β-hCG concentration greater than 4000 IU/L and that of the group with an initial β-hCG concentration less than 4000 IU/L, P=0.003<0.05, and the test indicated a significant difference. However, the success rate for the group with an initial β-hCG concentration greater than 4000 IU/L was still relatively high (61.22%).
3.4 Side effects
Of the 213 patients, 11 (5.16%) experienced nausea and vomiting after medication, which resolved without intervention, and 5 patients showed slight increases in transaminase levels, which was normal after hepatoprotective drug treatment; however, the other patients had no obvious adverse reactions.
3.5 Average hospital stay and total cost
The average hospital stay for conservative treatment in the successful treatment group was significantly shorter that in the failed treatment group, and the difference between the two groups was statistically significant (8.61±3.14 versus 10.62±3.39; Z=-3.39, P=0.000<0.001).
The total cost of conservative treatment for patients for whom treatment is successful in our hospital is generally approximately $437.83, and the cost for surgery over the same period is more than $1459.45.