Prognostic Language and Subsequent Code-Status Limitation After Acute Brain Injury: A Multidatabase Observational Study

Purpose. Prognostic assessments after acute brain injury are largely narrative, and how prognostic language relates to subsequent care has not been measured at scale. We quantified where it is written and its association with a subsequent code-status limitation. Materials and Methods. Multidatabase observational study of adults with acute brain injury or a related neurologic emergency, using MIMIC-IV (2008-2019; discharge summaries and radiology reports) and a timestamped MIMIC-III cohort (notes and code-status orders). The exposure was documented prognostic language; outcomes were its association with a subsequent full-code-to-limitation transition, note-stream location, and completeness of documented command-following relative to structured Glasgow Coma Scale (GCS) motor scores. Results. Among 31,993 admissions (27,054 patients; median age, 69 years; 54.9% male), prognostic language in the timestamped cohort (MIMIC-III) was associated with a subsequent code-status limitation after multivariable adjustment (adjusted hazard ratio, 4.3; 95% CI, 2.9-6.5; unadjusted 14-day cumulative incidence, 40% vs 8.5%), including the comfort-measures component (3.9), a higher-risk subgroup (4.4), and after acute-physiology adjustment (4.1); the association was concentrated in the first 3 days. Non-prognostic severity language showed no comparable association (hazard ratios, 1.1-1.3). Prognostic language localized almost entirely to the narrative (4.9% of discharge summaries vs 0.015% of radiology reports); command-following was undocumented in 55.7% of summaries, and no final-24-hour GCS motor score was charted in 72.8%. Conclusions. Documented prognostic language after acute brain injury was written in the narrative, not structured fields, and was associated with a subsequent code-status limitation after multivariable adjustment. This observational association cannot establish causation but warrants prospective study.