Incidence of gestational trophoblastic disease in South Korea: a longitudinal, population-based study

INTRODUCTION: We investigated the rate and longitudinal trends of gestational trophoblastic disease (GTD) incidence in the Republic of Korea between 2009 and 2015 using population-based data. MATERIALS AND METHODS: Data of patients diagnosed with GTD from 2009 to 2015 were obtained from the Health Insurance Review and Assessment Service/National Inpatient Sample (HIRA-NIS) in the Republic of Korea. The HIRA annually provides the HIRA-NIS, a collection of clinical data from over one million people. For each year, the HIRA-NIS extracted records of 13% of patients admitted at any one time during the year and 1% of all remaining patients using the weighted sample method. RESULTS: Medical records of 370,117 women with at least one pregnancy (GTD, ectopic pregnancy, abortion, or delivery) were extracted from a total of 4,476,495 records. Of these, 372 episodes of GTD were identified in women with a mean age of 35.4 ± 0.7 years. The incidence rate of GTD was 130 ± 10 cases per 100,000 pregnancies, which was classified as hydatidiform mole (HM), invasive mole, or malignant neoplasm of the placenta with incidence rates of 110 ± 10, 20 ± 0, or 10 ± 0 cases per 100,000 pregnancies, respectively. Incidence of GTD was lowest among women in their late 20 s and early 30 s. Occurrences of HM accounted for 80.3% all GTD cases. Weighted logistic analysis indicated that while age significantly affected the incidence of GTD (odds ratio (OR): 2.46; 95% confidence interval (CI) [1.79–3.37]; P < 0.001), socioeconomic status did not (OR: 1.94; 95% CI [1.0–3.79]; P = 0.05). CONCLUSIONS: In the Republic of Korea, we observed overall incidence rates of GTD and HM of 1.3 and 1.1 per 1,000 pregnancies, respectively, which are similar to those reported in recent Western population-based studies. We also noted that annual incidence rates of GTD stabilized from 2009 to 2015.