Clinical risk factors and outcomes of tumor lysis syndrome in hospitalized patients with malignancy.

e18635 Background: Tumor lysis syndrome (TLS) is a serious oncologic emergency that can occur in both hematologic and solid malignancies. Contemporary real-world data describing which clinical factors are associated with TLS and which factors drive mortality once TLS occurs are limited. Methods: We analyzed adult hospitalizations with TLS in the National Inpatient Sample (2016–2021) using ICD-10 codes. Survey-weighted analyses described baseline characteristics and outcomes. Multivariable survey-weighted logistic regression was used to identify independent predictors of in-hospital mortality, adjusting for age, sex, race, payer, income quartile, acute kidney injury (AKI), chronic kidney disease (CKD), hyperuricemia, dehydration, sepsis, metastatic disease, and hospital characteristics. Results: An estimated 88, 280 hospitalizations with TLS were identified; 82. 2% occurred in patients with hematologic malignancies and 17. 8% in those with solid tumors. Patients with TLS commonly had acute kidney injury (AKI) and sepsis, and solid-tumor TLS was frequently associated with metastatic disease. Crude in-hospital mortality among patients with TLS was 27. 8% in solid tumors and 14. 9% in hematologic malignancies (p<0. 001). After multivariable adjustment, the strongest independent predictors of in-hospital mortality were sepsis (adjusted odds ratio aOR 4. 67, 95% CI 4. 29–5. 09, p<0. 001), AKI (aOR 3. 66, 95% CI 3. 26–4. 12, p<0. 001), and metastatic disease (aOR 1. 48, 95% CI 1. 28–1. 72, p<0. 001). Compared with solid tumors, TLS associated with hematologic malignancies was independently associated with lower mortality (aOR 0. 69, 95% CI 0. 60–0. 80, p<0. 001). TLS associated with hematologic malignancies resulted in longer hospitalizations (mean length of stay 15. 4 vs 10. 2 days, p<0. 001) and higher total charges (mean 256, 980 vs 148, 140, p<0. 001). After adjustment, malignancy type was not independently associated with dialysis (aOR 1. 06, p=0. 54), ICU-level care (aOR 1. 30, p=0. 10), mechanical ventilation (aOR 0. 81, p=0. 13), or non-home discharge (aOR 0. 95, p=0. 40). Conclusions: Among hospitalized patients with TLS, sepsis, acute kidney injury, and metastatic disease are the dominant drivers of mortality, regardless of malignancy type. Although TLS occurs more frequently in hematologic malignancies, TLS associated with solid tumors carries a substantially higher risk of death. Early identification and aggressive management of high-risk patients may improve outcomes.