Hematologic Malignancies in Critical Care: A National Observational Comparison Between ICU and Non-ICU Patients.

PURPOSE: Critically ill patients with hematologic malignant (HM) diseases are a heterogeneous but vulnerable group, where intensive care (ICU) is associated with high mortality. The impact of ICU care on long-term survival is less well described. This retrospective national cohort study investigates the long-term survival outcomes of hospitalized HM patients, comparing ICU survivors with non-ICU patients. In addition, focused analyses were performed on the ICU cohort to further investigate survival patterns. METHODS: Adult patients diagnosed with HM and admitted to hospital between May 6, 2014, and December 31, 2019, were identified through the National Patient Registry. ICU admissions from these patients were obtained from the Norwegian Intensive Care and Pandemic Registry. Survival was measured from the time of first diagnosis until death or December 31, 2020. The patients were divided into three diagnostic groups: lymphoma, chronic leukemia, myeloma and acute leukemia. RESULTS: Among 26,281 hospitalized patients with HM, 2094 required ICU care. Long-term survival from diagnosis to end of follow up varied significantly by ICU status. Compared with patients who never required ICU, mortality rose sharply during ICU care (HR 148; 95% CI 133-165) and remained elevated after discharge (HR 4.47; 95% CI 4.42-5.07). Acute leukemia was identified as a strong risk factor (HR 4.27; 95% CI 3.99-4.56). In the focused ICU cohort analyses, ICU survival was 81%, and one-year post-ICU survival was 45%. Acute leukemia and elevated SAPS II score, but not allogeneic transplant status, independently predicted ICU mortality. CONCLUSION: While most HM patients survive ICU admission, long-term survival is decreased compared with non-ICU patients. EDITORIAL COMMENT: This analysis of hematological malignancy cases in Norway presents and compares outcomes for those in the subgroup requiring intensive care treatment, compared to those not requiring care in the intensive care unit. Intensive care unit survival was high, but severity of illness in the ICU was associated with worse long-term survival.