PURPOSE: Contemporary data on mortality of hematological patients admitted to the intensive care unit (ICU) are missing. In a Danish nationwide set-up, we assessed 30-day and 1-year mortality in this population including impact of age and comorbidity, with non-hematological patients as reference.

METHODS: This population-based cohort study included all non-surgical patients > 15 years of age admitted to an ICU in Denmark between 2010 and 2015. Data on hematological malignancies were obtained from the Danish Hematological Database, and information on the Charlson Comorbidity Index was obtained from the Danish National Patient Registry. Thirty-day and 1-year mortality was estimated using the Kaplan-Meier method. We used Cox proportional hazards regression to estimate hazard ratios.

RESULTS: We included 2122 ICU patients with a hematological malignancy and 88,951 non-hematological ICU patients. The 30-day mortality was 44% (95% confidence interval: 42-47%) among hematological patients and 27% (27-27%) among non-hematological patients. Similarly, 1-year mortality was 66% (64-68%) and 37% (37-37%), respectively. The corresponding hazard ratio with adjustment for age, sex, and comorbidity was 1.62 (1.54-1.71). Excess mortality was observed in all subgroups of age or of comorbidity. For example, the 1-year mortality for patients with Charlson Comorbidity Index Score > 3: 70% (66-74%) among hematological patients and 62% (61-63%) among non-hematological patients.

CONCLUSION: ICU patients with hematological malignancy had higher mortality than other ICU patients. However, one third of critically ill patients with a hematological malignancy is alive 1 year after ICU admission.