EPID-15. INPATIENT CARE COSTS AND ASSOCIATED REIMBURSEMENTS FOR PATIENTS WITH LEPTOMENINGEAL DISEASE: A REAL-WORLD ANALYSIS

Abstract INTRODUCTION Leptomeningeal disease (LMD) is an increasingly significant cause of cancer-related morbidity, mortality, and economic burden. While healthcare costs associated with brain metastases (BMs) have been well-described, minimal economic literature exists for LMD. This study sought to evaluate inpatient care costs (IPCCs) and reimbursements for LMD patients using a contemporary US claims database. METHODS This retrospective study, reported following STROBE guidelines, included adult LMD patients (aged 18-65 years) receiving inpatient care during January 2016 to December 2021 in TruvenHealth MarketScan Commercial Claims and Encounters Database, currently the largest US commercial insurance database. Patient selection using ICD-10 codes, data management, and statistical analyses were performed in Stata/SE18.0. Demographic, clinical, and financial attributes were summarized through descriptive statistics. IPCC measures were adjusted using 2023 Consumer Price Index Medical Care component. Primary study outcome was adjusted gross total payments (total IPCC). Given skewness in IPCC, log-transformation was carried out, followed by multivariable linear regression using socio-demographic, clinical and insurance-related characteristics to identify significant covariates. RESULTS A total of 1047 inpatient admissions across 1010 LMD patients were included. 43.8% (N=442) had brain metastases (BM) concomitantly present while 56.2% (N=568) did not. Primary tumor associated with LMD comprised of: lung and/or lower respiratory tract cancer (18%), breast cancer (6.6%), and melanoma (6.1%). 54.8% (N=554) did not have any bone metastases and 78.6% (N=794) did not have any liver metastases. Per inpatient admission, median adjusted values of gross total payments were $32603.6 (IQR $19967-64960) and gross payments to principal physician $1119.26 (IQR $532.41-2919.78), being 3.4% of total payments. Covariates associated with significantly higher total IPCC included age, male sex, length -of-stay, whole brain radiotherapy, and admission year, while cancer from lung and melanoma, medical and psychiatric admission (versus surgical), and drug claims capture were associated with significantly lower IPCC. CONCLUSIONS Contemporary IPCCs for LMD patients in US are substantial but driven minimally by payments to principal physician for services rendered.