J Korean Med Sci. 2021 Mar 29;36(12):e79 https://doi.org/10.3346/jkms.2021.36.e79 eISSN 1598-6357·pISSN 1011-8934 Original Article Performance Changes Following the Cell Therapy & Organ Transplantation Revision of Organ Allocation System of Lung Transplant: Analysis of Korean Network for Organ Sharing Data Hye Ju Yeo ,1,2 Do Hyung Kim ,3 Yun Seong Kim ,1 Doosoo Jeon ,1 and Woo Hyun Cho 1,2 1Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea Received: Aug 4, 2020 2Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Accepted: Jan 13, 2021 Yangsan Hospital, Yangsan, Korea 3Department of Thoracic and Cardiovascular Surgery, Pusan National University Yangsan Hospital, Yangsan, Address for Correspondence: Korea Woo Hyun Cho, MD Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine and Research Institute for ABSTRACT Convergence of Biomedical Science and Technology, Pusan National University Background: There is currently a lack of data on the impact of the recent revision of the Yangsan Hospital, 20 Geumo-ro, Mulgeum- eup, Yangsan 50612, Republic of Korea. domestic lung allocation system on transplant performance. E-mail: [email protected] Methods: We conducted a retrospective analysis of transplant candidates and transplant patients registered in Korean Network for Organ Sharing between July 2015 and July 2019. Study © 2021 The Korean Academy of Medical periods were classified according to the introduction of the revised lung allocation system as Sciences. This is an Open Access article distributed follows: period 1 from July 2015 to June 2017 and period 2 from August 2017 to July 2019. under the terms of the Creative Commons Results: During the study period, a total of 627 patients were on the waiting list, of which Attribution Non-Commercial License (https:// 398 lung transplantations were performed. Total waiting list size increased by 98.6%, from creativecommons.org/licenses/by-nc/4.0/) 210 in period 1 to 417 in period 2. The number of transplant patients also increased by 32.7%, which permits unrestricted non-commercial from 171 in period 1 to 227 in period 2. The number of donors decreased from 1,042 to 878, use, distribution, and reproduction in any whereas the usage rate, i.e., the number of lung donors used for transplantation among the medium, provided the original work is properly cited. total number of reported lung donors, increased from 16.4% to 25.9%. The proportion of patients with high urgent status at transplantation increased from 45% to 60.4%, whereas ORCID iDs those with urgent status decreased from 46.8% to 35.7% (P = 0.006). The use of marginal Hye Ju Yeo donor lungs increased from 29.8% to 53.7% (P < 0.001). To adjust urgency status and https://orcid.org/0000-0002-8403-5790 Do Hyung Kim marginal donor usage between two groups, we conducted a propensity score matching https://orcid.org/0000-0002-8774-3397 analysis. No significant differences were detected in 1-year survival rates between the two Yun Seong Kim periods after propensity score matching. As well, no significant difference was observed in https://orcid.org/0000-0003-4328-0818 mortality on the waiting list between the two periods. Doosoo Jeon Conclusion: The recent revision of the lung allocation system in Korea did not change the https://orcid.org/0000-0002-8206-9487 Woo Hyun Cho performance of lung transplant in terms of waiting list mortality and 1-year survival. The https://orcid.org/0000-0002-8299-8008 rapid increase in the volume of waiting list between the two periods increased the waiting time, transplantation of high-urgency patients, and use of marginal lung donors. Funding This study was supported by a 2020 research Keywords: Lung Transplantation; Lung Allocation System; Korea; Mortality grant from Pusan National University Yangsan Hospital. https://jkms.org 1/11 Current Lung Allocation System in Korea Disclosure INTRODUCTION The authors have no potential conflicts of interest to disclose. Lung transplantation is the only lifesaving option for patients with end-stage lung diseases. Author Contributions Studies have reported that approximately 5,000 lung transplantations were performed Conceptualization: Cho WH. Methodology: annually at the global level, and 90 transplantations were performed in Korea.1,2 The number Kim DH. Formal analysis: Yeo HJ. Data of patients on the lung transplant waiting list in Korea increased steadily up to 197 and curation: Jeon D. Validation: Kim YS. Writing exceeded the number of transplantation procedures performed every year.2 Unfortunately, a - original draft: Yeo HJ. Writing - review & editing: Cho WH. Approval of final manuscript: shortage of donor lungs inevitably results in considerable numbers of patient deaths on the all authors. waiting list. An efficient donor organ allocation system remains crucial in optimizing donor use and to balance waiting list mortality and improve transplant outcomes.3 Current donor lung allocation systems in Korea are based on urgency, without survival benefit being the accepted primary goal.4 Allocation systems are based on various factors, including geographical (regional) accumulated waiting time, audit-derived urgency criteria, and individual clinical profile. Our national policy constitutes several of these criteria used in combination. However, weighing of these factors differs between different countries such as USA and Europe.5-7 In July 2017, Korea revised the lung allocation system from the one based on urgency and waiting time to a system based on urgency, blood type, and region. However, till date, there is a lack of information assessing the impact of the current lung allocation system on transplant performance in Korea. Therefore, this study was conducted to evaluate the performance of the recent revision of the lung allocation system in Korea. METHODS We retrospectively reviewed and analyzed the Korean Network for Organ Sharing (KONOS) database. Collected data included donor, candidate, and recipient information such as age, sex, region of registration, date of registration, diagnosis, ABO blood type, urgent status at registration, death on the waiting list, date of transplantation, urgent status at transplantation, and date of death after transplantation. Study periods were classified according to the lung allocation system as follows: period 1 from July 2015 to June 2017 and period 2 from August 2017 to July 2019. We compared the transplant outcomes and waiting list mortality between the two periods. We included only newly registered lung transplant candidates during the study period for the analysis of candidates. Survival status and date of death were collected till July 2020 for all patients included in this study. Classification of diagnosis KONOS collects the underlying disease in the following 12 categories: idiopathic pulmonary fibrosis (IPF), sarcoidosis, bronchiectasis, bronchiolitis obliterans after transplant, emphysema, lymphangioleiomyomatosis, asbestosis, primary pulmonary hypertension, cystic fibrosis, Eisenmenger syndrome, other, and unknown. We classified the underlying disease into the following 5 categories: chronic obstructive pulmonary disease (COPD; emphysema), interstitial lung disease (ILD, idiopathic pulmonary fibrosis, sarcoidosis, lymphangioleiomyomatosis, asbestosis), primary pulmonary hypertension, bronchiectasis (cystic fibrosis), and other (Eisenmenger syndrome, bronchiolitis obliterans after transplant, other and unknown). https://jkms.org https://doi.org/10.3346/jkms.2021.36.e79 2/11 Current Lung Allocation System in Korea Lung allocation policy changes Before the implementation of the system in July 2017, all donor lungs were allocated according to an urgency tier system. Patients were classified as status 0, 1, 2, 3 and 7 Supplementary( Table 1). Patients with status 0 were defined as those who require mechanical ventilation or extracorporeal membrane oxygenation (high urgent status). Those with status 1 (urgent status) were defined as having one or more of the following conditions: 1) New York Heart Association (NYHA) IV and PaO2 < 55 mmHg on arterial blood gas test measured without oxygen administration, 2) NYHA IV and mean pulmonary arterial pressure > 65 mmHg or mean right atrial pressure > 15 mmHg, and 3) cardiac index < 2 L/min/m2. Status 2 were defined as having one or more of the following conditions: 1) In the pulmonary function test, forced expiratory volume at 1 second (FEV1) < 25%, 2) PaO2 < 60 mmHg in arterial blood gas test measured without oxygen, 3) When the average right atrial blood pressure is 10–15 mmHg, 4) When the average pulmonary arterial pressure is 55–65 mmHg, 5) Cardiac index < 2–2.5 L/min/m2. Status 3 were defined as having one or more of the following conditions: 1) When a single lung transplant is required, 2) Emphysema, pulmonary hypertension, diffuse interstitial lung disease, 3) Forced expiratory volume < 30% in pulmonary function test, 4) If hospitalized more than 3 times for respiratory failure. Status 7 was defined as whose status does not meet 0–3. Status from 2 to 7 was considered an elective status. Patients with status 0 (high urgent status) were prioritized over those with status 1 to 7. Moreover, within the same urgency tier, patients with the longest waiting period received the lung donation first. In July 2017, the Korea organ commission of the Korea medical council decided to change the