| Objective: The main purpose of this study was to explore the diagnostic value and optimal cut-off value of basic gonadotropin and its ratio in girls with central precocious puberty.Methods: From June 2017 to June 2022,the gonadotropin-releasing hormone stimulation test was performed in the second affiliated Hospital of Anhui Medical University because of breast development at the age of 6 to 8 years.According to the experimental design,a total of 477 cases were included in the study.The peak level of luteinizing hormone after Gn RH stimulation test was higher than that diagnosed by 5IU/L as central precocious puberty.According to the results of diagnosis,447 cases were divided into two groups: CPP group(n=177)and non-CPP group(n=270).Finally,the patients older than 8years old and less than 8 years old were analyzed separately,and the grouping method was also grouped according to the diagnostic results.The correlation between each index and the diagnosis of central precocious puberty was analyzed by binary Logistic regression.The ROC curves of basic luteinizing hormone,follicle stimulating hormone and their ratio were drawn.The area under the curve and 95% confidence interval of each curve are measured.The diagnostic value and the best cut-off value of basic luteinizing hormone,follicle-stimulating hormone and their ratio in central precocious puberty were obtained.Results:(1)There were significant statistical differences in general data such as Chronologicalage age,bone age,BA-CA and ovarian volume between CPP group and non-CPP group.The age and bone age of CPP group were significantly higher than those of non-CPP group.There was no significant difference in pituitary volume between the two groups.(2)There were significant statistical differences in basal LH value,basal LH/FSH value and basal FSH ratio between the two groups.The basal LH value and the median value of basal FSH in CPP group were higher than those in non-CPP group.(3)The area under the ROC curve corresponding to the basal luteinizing hormone level is the largest,with the maximum AUC value of 0.767,95%confidence interval(CI),6.02–28.19,followed by basal FSH level(AUC,0.742;95%CI,1.60–2.29).The basal LH/FSH ratio had a relatively low diagnostic value(AUC,0.681;95% CI,1.22–6.39).(4)In the overall data,The best cutoff value for CPP diagnosis by basal LH was0.545 IU/L(sensitivity,48.3%;specificity,92.8%).Judging by the ROC curve when the Youden index reached the maximum,the sensitivity and specificity of the diagnosis were 48.3% and 92.8%,respectively.When the basic LH value is1.82IU/L,the sensitivity for the diagnosis of central precocious puberty is100%,but the specificity is only 1.43%.(5)Among the patients over 8 years old,the area under the curve(AUC)of the ROC curve corresponding to the basic LH level was the largest,and the maximum AUC value was 0.849,95%,3.66-49.38,and the critical value between 0.425IU/L and the diagnosis of central precocious puberty was0.425IU/L.Judging by the ROC curve when the Youden index reached the maximum,the diagnostic sensitivity was 70.7% and the specificity was 89.2%.In patients under the age of 8,the critical value between the basic LH level and the diagnosis of central precocious puberty was 0.515IU/L,with a sensitivity of36.4% and a specificity of 91.4%.Conclusion: In the girls with early development of secondary sexual characteristics,the basic LH value has a good diagnostic value,and it can be diagnosed as CPP when the basic value of LH is 0.545IU/L,so as to avoid Gn RH stimulation test.And the diagnostic value is greater in girls over 8 years old.Basal gonadotropin and basal luteinizing hormone / basal follicle stimulating hormone are important predictors for the diagnosis of central precocious puberty. |
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