Outcomes of Tumor Lysis Syndrome in Hospitalized Patients: A Retrospective Cohort Study from National Inpatient Sample 2016-2019

Background: Tumor lysis syndrome (TLS) is an oncologic emergency caused by rapid cell lysis spilling intracellular contents (potassium, phosphate, and nucleic acids) into the systemic circulation leading to hyperkalemia, hyperphosphatemia, secondary hypocalcemia, hyperuricemia, and acute kidney injury. We aim to study outcomes like in-hospital mortality, length of stay (LOS) and associated complications among TLS patients.

Methods: This is a retrospective cohort study from TLS hospitalizations between January 1, 2016, and December 31, 2019, using the 2016-2019 National Inpatient Sample (NIS), the largest all-payer public database of hospital care data in the United States. Our study sample included, TLS hospitalizations with age 18 years or older, using the ICD 10 diagnosis codes validated in previous studies.

Results: From 2016 to 2019, the incidence rate of TLS was 36 per 100,000 (N=10,277) hospitalizations. Among TLS admissions, 36.9% (n= 3794) were females and mean age was 63±15.5 years (P<0.001). Moreover, 67.5% were Whites, 14.7% were Blacks, 9.4% were Hispanics, and 3.7% were Asians. A total of 2494(47%) hospitalizations had a Charlson Comorbidity index (CCI) of three or higher. TLS hospitalizations were complicated by sepsis (10.6%, N=1089), Cardiac arrest (2.9%, N=298), AKI (68.8%, N=7072), ARDS (0.6%, N=64, requirement for dialysis (8.8%, N=906), GI bleed (5.5%, N=568), Non-traumatic brain hemorrhage (1.4%, N=142), Hyperkalemia (29%, N=2976), Hypocalcemia (10%, N=1042), requirement of mechanical ventilation (11%, N=1130). Mean length of stay was 13.7 days±14.6. Multivariate regression analysis showed that, the predictors for increased in-hospital mortality were GI bleed(aOR: 1.43; 95% CI: 1.16, 1.7; p=0.001), Sepsis (aOR: 2.77; 95% CI: 2.35, 3.25; p<0.001), AKI (aOR: 2.89; 95% CI: 2.49, 3.35; p<0.001), hyperkalemia (aOR: 1.54; 95% CI: 1.37, 1.73; p<0.001) after controlling for age, race ,gender, regional location of the hospital, and income. Females have higher in hospital mortality from TLS compared to males (aOR: 1.22; 95% CI: 1.09, 1.36; p=0.001). From 2016-2019, the annual incidence of TLS per 100,000 hospitalizations has been increasing at 28.6 in 2016, 33.3 in 2017, 38.3 in 2018 and 44.3 in 2019 (p-trend<0.001).

Conclusion: Increased incidence of in hospital mortality could be attributed to GI bleed, hyperkalemia, sepsis, AKI. The annual incidence of TLS is rising every year.

No relevant conflicts of interest to declare.