Dual pathology, amplified risk? Understanding outcomes in TLS with concurrent heart failure.

e18618 Background: Tumor lysis syndrome (TLS) is a life-threatening oncological emergency that is associated with end-organ dysfunction and high mortality. Co-existing heart failure (HF) may further worsen the clinical outcome, particularly given the central role of aggressive fluid resuscitation in TLS management. There is a paucity of population-level data comparing outcomes in TLS patients with and without concomitant HF, and this study aims to address that gap. Methods: We retrospectively analysed adult hospitalizations (≥18 years) in the National Inpatient Sample (NIS) from 2018-2021using ICD-10 codes to identify TLS (ICD-10: E88.3) and HF (ICD-10: I50). Baseline characteristics and clinical outcomes – including mortality, length of stay (LOS), and inflation-adjusted charges – were extracted. Adjusted odds ratios (aORs) and beta coefficients (βs) were calculated for different outcomes using multivariable regression analyses that accounted for demographic, clinical, and hospital-level factors. Results: Among 61,705 hospitalizations for TLS, 11,780 patients had co-exsisting HF. Patients who had HF were older (Median age 71 vs. 65 years, p<0.001), with similar sex distribution (38% vs. 37% females). Compared with those without HF, the HF group had lower burden of solid tumors (49% vs. 56%) and acute myeloid leukemia (2.9% vs. 7.2%) but higher burden of acute lymphoblastic leukemia (18% vs 14%), chronic lymphocytic Lymphocytic leukemia (7 4% vs. 5.2%), and multiple myeloma (7.8% vs. 5.5%). Chronic myeloid leukemia burden was similar in both groups (3.0% vs. 3.1%). Admitted patients for TLS with HF (vs without HF) had worse outcomes in terms of mortality (29% vs. 23%; aOR: 1.40 [1.23, 1.58]), acute kidney injury (81% vs. 68%; aOR 1.44 [1.27, 1.63]), need for renal replacement therapy (18% vs. 13%; aOR 1.35 [1.15, 1.57]), sepsis (33% vs. 27%; aOR 1.42 [1.26, 1.60]), respiratory failure (50% vs. 30%; aOR 2.24 [2.01, 2.49]), need for mechanical ventilation (19% vs. 15%; aOR 1.43 [1.23, 1.65]), and cardiac arrythmias (47% vs. 19%; aOR 2.90 [2.57, 3.27]). TLS patients with HF had longer LOS (β = +2.6 days [1.8, 3.3], p<0.001), higher healthcare costs (β = +64,972$, p<0.001), and increased non-home discharges (aOR 1.43 [1.28, 1.60]), when compared to those without HF. Conclusions: Among patients hospitalized with TLS, concomitant HF had worse clinical outcomes in patients, including mortality, sepsis, respiratory failure, need for mechanical ventilation, acute kidney injury, renal replacement therapy, and cardiac arrhythmias. These patients experienced longer LOS, higher healthcare costs, and more non-home discharges. A multidisciplinary approach is needed to manage these high risk patients for optimal care and to prevent adverse in-hospital outcomes.