Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.