Endourology & Stone Disease(구연) Oral Session 6 / Endourology & Stone Disease (Ⅰ) (O-055) Crystal A (3F) 11월28일(수) 14:00-15:00 Analysis of factors affecting re-admission after retrograde intrarenal surgery for renal stone 분당서울대학교병원 비뇨의학과 김태진,이민승,이동환,이학민,홍성규,변석수,오종진 Objective To investigate the factors associated with hospital readmission (HR) after retrograde intrarenal surgery (RIRS) among renal stone patients. Patients and methods The study included patients who underwent RIRS from June 2011 to December 2017. Patients who were readmitted due to surgery related complications were evaluated retrospectively. Patient demographics including age, medical comorbidity, body mass indices, ASA score, perioperative parameters and stone factors were compared with total cohorts. HR was defined as visits to the Emergency Room or unplanned admission within 30 days after discharge. The factors affecting HR rates were analyzed using uni- and multi-variate analysis. Results A total of 572 patients were enrolled into the study. The mean age was 57.6 ± 14.1 years and the mean stone diameter was 13.4 ± 6.2 mm. The mean complication rate was 6.1% and the median hospitalization time was 2.1 ± 3.4days. HR occurred in 20 patients (3.5%). Compared to non-admission patients, readmitted patients had a higher rate of bilateral RIRS (20.0% vs 12.2%, p = 0.035), number of stones (4.65 vs 2.2, p = 0.041) and higher stone complexity score (4.15 vs 2.11, p = 0.003). Multivariate analysis showed bilateral RIRS (OR = 1.091, p = 0.031) and stone complexity (OR = 1.405, p = 0.003) were significant factors to predict re-admission after RIRS. Conclusions Patients with complex renal stones or those who underwent bilateral RIRS were more likely to have a higher rate of re-admission. Proper perioperative management to prevent complications should be planned based on these predictive factors. keywords : Retrograde Intrarenal Surgery, Hospital readmission, Renal stone,