Mechanical ventilation timing categories and inpatient outcomes in adult cancer hospitalizations: A 2018–2022 National Inpatient Sample analysis.

e23095 Background: Mechanical ventilation (MV) during cancer hospitalizations is commonly evaluated as a binary event, potentially obscuring heterogeneity in escalation trajectories. The association between length-of-stay–based MV timing categories and distinct inpatient patterns of severity and resource intensity among hospitalized adults with malignancy was examined. Methods: We performed a serial cross-sectional analysis of adult hospitalizations with a principal diagnosis of malignancy in the 2018–2022 Healthcare Cost and Utilization Project National Inpatient Sample. MV was identified using ICD-10-PCS procedure codes and categorized as no MV, early MV (LOS ≤3 days), intermediate MV (LOS 4–9 days), or late MV (LOS ≥10 days) as an administrative timing proxy. Outcomes included in-hospital mortality (primary), shock and dialysis-requiring acute kidney injury as escalation-associated endpoints, LOS, hospitalization cost derived using cost-to-charge ratios, and APR-DRG severity of illness subclass. National estimates were generated using survey-weighted analyses incorporating discharge weights with hospital-level clustering and stratification. Results: Among an estimated 4,809,239 cancer hospitalizations nationally, MV occurred in 2.6% of admissions, distributed as 0.31% early MV, 0.70% intermediate MV, and 1.58% late MV. Mortality differed markedly by MV timing: 3.40% among non-ventilated admissions versus 66.65% for early MV, 42.80% for intermediate MV, and 35.47% for late MV. Early MV corresponded to a rapid escalation trajectory with very short LOS (1.84 days), high APR-DRG severity (3.74), and high shock prevalence (25.36%). Intermediate MV admissions had LOS similar to non-ventilated admissions (6.53 vs 6.52 days) but substantially higher mortality (42.80% vs 3.40%), higher shock prevalence (17.82%), and higher mean costs ($42,394 vs $28,448). Late MV corresponded to prolonged critical illness with extreme resource utilization, including LOS of 25.89 days and mean cost of $132,530; late MV admissions had the highest dialysis-requiring acute kidney injury prevalence (10.25%) and the highest APR-DRG severity (3.89). Conclusions: LOS-defined MV timing categories group adult cancer hospitalizations into distinct escalation-associated trajectories with large differences in mortality, severity, and resource intensity. Timing-based MV gives an insight into cancer patients’ hospital course and will aid in future research into prognosis of hospitalized cancer patients.