Identifying pregnancy episodes and estimating the last menstrual period using an administrative database in Korea: an application to patients with systemic lupus erythematosus

• Published in: Epidemiology and health Vol. 46; pp. e2024012 - 012
• Main Authors: Jung, Yu-Seon, Song, Yeo-Jin, Keum, Jihyun, Lee, Ju Won, Jang, Eun Jin, Cho, Soo-Kyung, Sung, Yoon-Kyoung, Jung, Sun-Young
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Society of Epidemiology 01.01.2024; 한국역학회
• Subjects: administrative claims healthcare; algorithms; Cyclophosphamide - adverse effects; Female; Humans; immunosuppressive agents; Immunosuppressive Agents - therapeutic use; Infant, Newborn; lupus erythematosus systemic; Lupus Erythematosus, Systemic - complications; Lupus Erythematosus, Systemic - drug therapy; Lupus Erythematosus, Systemic - epidemiology; Mycophenolic Acid - therapeutic use; Original; Pregnancy; Pregnancy Outcome; Premature Birth - chemically induced; Premature Birth - drug therapy; Republic of Korea; 예방의학; Republic of Korea; Pregnancy; Algorithms; Administrative claims healthcare; Pregnancy outcome; Immunosuppressive agents; Lupus erythematosus systemic
• ISSN: 2092-7193; 2092-7193
• DOI: 10.4178/epih.e2024012

OBJECTIVES: This study developed an algorithm for identifying pregnancy episodes and estimating the last menstrual period (LMP) in an administrative claims database and applied it to investigate the use of pregnancy-incompatible immunosuppressants among pregnant women with systemic lupus erythematosus (SLE).METHODS: An algorithm was developed and applied to a nationwide claims database in Korea. Pregnancy episodes were identified using a hierarchy of pregnancy outcomes and clinically plausible periods for subsequent episodes. The LMP was estimated using preterm delivery, sonography, and abortion procedure codes. Otherwise, outcome-specific estimates were applied, assigning a fixed gestational age to the corresponding pregnancy outcome. The algorithm was used to examine the prevalence of pregnancies and utilization of pregnancy-incompatible immunosuppressants (cyclophosphamide [CYC]/mycophenolate mofetil [MMF]/methotrexate [MTX]) and non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy in SLE patients.RESULTS: The pregnancy outcomes identified in SLE patients included live births (67%), stillbirths (2%), and abortions (31%). The LMP was mostly estimated with outcome-specific estimates for full-term births (92.3%) and using sonography procedure codes (54.7%) and preterm delivery diagnosis codes (37.9%) for preterm births. The use of CYC/MMF/MTX decreased from 7.6% during preconception to 0.2% at the end of pregnancy. CYC/MMF/MTX use was observed in 3.6% of women within 3 months preconception and 2.5% during 0-7 weeks of pregnancy.CONCLUSIONS: This study presents the first pregnancy algorithm using a Korean administrative claims database. Although further validation is necessary, this study provides a foundation for evaluating the safety of medications during pregnancy using secondary databases in Korea, especially for rare diseases.