Lymphocyte trajectories as prognostic indicators in intracerebral hemorrhage: a MIMIC-IV cohort study.

To examine the association between lymphocyte count trajectories and clinical outcomes in patients with spontaneous intracerebral hemorrhage (ICH) using data from the MIMIC-IV database. Patients with spontaneous ICH and at least two lymphocyte count measurements within the first 7 days of ICU admission were identified from the MIMIC-IV database. Latent growth mixture modeling was used to determine distinct lymphocyte trajectory groups. Kaplan-Meier survival curves and Cox proportional hazards models were employed to assess associations with mortality. Clinical characteristics and ICU length of stay were also compared between trajectory classes. A total of 841 patients were included. Two distinct lymphocyte trajectory classes were identified: Class 1 ("Increasing lymphocyte count") and Class 2 ("Decreasing lymphocyte count"). Kaplan-Meier analysis revealed significantly lower survival in Class 2 (p = 0.00046). Cox regression confirmed a higher mortality risk in Class 2 compared to Class 1. Patients in Class 2 also had significantly longer ICU stays (mean: 29.83 vs. 18.34 days, p < 0.01) and worse clinical outcomes. Subgroup analyses indicated that age, sex, BMI, diabetes status, and Glasgow Coma Scale (GCS) scores were associated with trajectory classification and mortality risk. Lymphocyte count trajectories are prognostically significant in patients with ICH. A decreasing lymphocyte trend is associated with higher mortality and prolonged ICU stays. Early identification of these patterns may improve risk stratification and guide targeted interventions. Further studies should explore underlying mechanisms.