Short-term mortality after intensive care admission in acute lymphoblastic versus predominantly acute myeloid leukemia: a retrospective cohort study using MIMIC-IV with eICU external replication

Vollständiger Abstract

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Background Adults with acute leukemia admitted to intensive care have high early mortality. Whether acute lymphoblastic leukemia (ALL) adds prognostic information beyond baseline severity remains clinically important. Methods We performed a retrospective MIMIC-IV cohort study of 486 first ICU stays from 372 adults with acute leukemia. Primary outcomes were hospital and ICU mortality. ALL was compared with a predominantly acute myeloid leukemia comparator using complementary confounder-only and severity-adjusted models and ICD-derived remission stratification, with directional replication in an independent eICU cohort. Results ALL admissions were younger and less severely ill at ICU entry. Crude hospital mortality was lower in ALL than in the predominantly AML comparator (23.8% vs. 38.6%; P = 0.010). After adjustment for age and comorbidity alone, ALL showed a non-significant reduction in the odds of hospital mortality (adjusted OR, 0.688; 95% CI, 0.385-1.228). Adding first-day Sequential Organ Failure Assessment (SOFA), which partly overlaps with leukemia-related complications, moved this estimate toward the null (adjusted OR, 0.905; 95% CI, 0.485-1.689). ICU-mortality estimates were also non-significant, although the severity-adjusted ICU estimate crossed the null (confounder-only adjusted OR, 0.690; severity-adjusted OR, 1.076). Because first-day SOFA may lie on the subtype-to-outcome pathway, the confounder-only estimate is reported as the total-association estimate (not conditional on the possible mediator), and all confidence intervals remained wide. Model calibration and discrimination were acceptable. In an independent eICU cohort (n=82), the crude and severity-adjusted ALL estimates for hospital mortality (odds ratios 0.667 and 0.445) were likewise non-significant. Conclusion In MIMIC-IV, the crude ALL survival advantage narrowed after adjustment and was not statistically significant. In eICU, crude and severity-adjusted estimates were likewise non-significant but moved further from, rather than toward, the null. Wide confidence intervals in both cohorts, the small ALL sample, overlap between first-day SOFA and leukemia-related complications, and unmeasured leukemia-specific factors leave a modest residual subtype effect possible. These are within-ICU associations affected by selection into intensive care; incomplete post-discharge death ascertainment mainly limits longer-horizon interpretation.