Risk Factors for 90-Day Readmission Among Patients with Metastatic Spine Tumors in South Korea: A Nationwide Population-Based Study

BACKGROUND: Population-based studies on the cause of readmission within 90 days after surgery or radiotherapy for metastatic spine tumors are scarce. We aimed to investigate the risk factors for readmission within 90 days after initial surgical or radiation treatment for metastatic spine tumors. METHODS: Patients who were diagnosed with metastatic spine tumors between 2012 and 2019 and underwent spinal magnetic resonance imaging within 1 year were classified according to treatment (surgical or radiotherapy groups), and the causes of the 90-day readmission and patient characteristics were compared. RESULTS: Overall, data from 15,815 patients (surgical group, 13,974 patients; radiotherapy group, 1841 patients) were evaluated. Radiotherapy was preferred in younger and male patients with a high Charlson Comorbidity Index, whereas surgery was mainly performed in patients with lumbar metastasis. Radiotherapy, age of 30e69 years, male sex, and Charlson Comorbidity Index >1 increased the risk of 90-day readmission in patients with metastatic spine tumors. The main causes of 90-day readmission among patients with metastatic spine tumors who received radiotherapy included tumor recurrence, chemotherapy, radiotherapy, and treatment of other organ metastases with radiotherapy. CONCLUSIONS: These study findings offer a better understanding of the causes of readmission following radiotherapy or surgical treatment in patients with metastatic spine tumors, and these results can help reducepostoperative morbidity and medical costs among these patients.