Thrombocytopenia as a predictor of hematoma expansion and mortality in intracerebral hemorrhage

Background and aims: There is limited data regarding the association between thrombocytopenia and outcomes of patients with intracerebral hemorrhage (ICH). We investigated whether thrombocytopenia predicts hematoma expansion and hospital mortality in ICH. Methods: This was a retrospective cohort analysis of consecutive patients with spontaneous ICH admitted to a tertiary hospital from 2010 to 2024. We tested the association between baseline thrombocytopenia (platelet count < 150 × 10 9 /L) at the time of the index ICH and both hematoma expansion (absolute increase > 6 mL or relative increase > 33%) and hospital mortality using multivariable logistic regression. Secondary analyses were undertaken to compare outcomes between patients with moderate-to-severe thrombocytopenia (platelet count < 100 × 10 9 /L) and mild thrombocytopenia (platelet count 100–149 × 10 9 /L) and between patients with thrombocytopenia who received platelet transfusion vs no transfusion. Results: We included 1002 patients (median (IQR) age, 73 (61–82); 448 females (44.7%) of whom 168 (16.8%) had thrombocytopenia). At baseline, patients with thrombocytopenia had lower Glasgow Coma Scale (GCS) scores (12 (6–15) vs 14 (9–15) P < 0.001), larger median hematoma volumes (21.4 mL (7.8–56.1) vs 15.3 mL (4.9–43.9), P = 0.004), more intraventricular hemorrhage (IVH) (84/168 (50.0%) vs 320 (38.4%), P = 0.005), and higher ICH scores (2 (1–3) vs 1 (0–3), P < 0.001) compared to those without thrombocytopenia. Hematoma expansion was more frequent in patients with thrombocytopenia (62/136 (45.6%) vs 233/738 (31.5%), P = 0.002); however, no association was present in adjusted analysis (adjusted odds ratio (OR) 1.28 (95% CI, 0.82–2.00), P = 0.269). With exclusion of platelet transfusion as a covariate from the adjusted model, thrombocytopenia was associated with hematoma expansion (OR 1.77 (95% CI, 1.20–2.59), P = 0.004). Thrombocytopenia was independently associated with hospital mortality (77/168 (45.8%) vs 199/834 (23.9%); OR 2.09 (95% CI, 1.24–3.53), P = 0.006). Among patients with thrombocytopenia, a platelet count < 100 × 10 9 /L was associated with more hematoma expansion in univariable (26/44 (59.1%) vs 36/92 (39.1%), P = 0.030) but not multivariable analysis (OR 1.66 (95% CI, 0.58–4.80), P = 0.348). Platelet transfusion predicted hematoma expansion in univariable (23/33 (66.7%) vs 40/103 (38.8%), P = 0.006) but not multivariable analysis (OR 2.74 (95% CI, 0.86–8.75), P = 0.090). Conclusions: Our findings suggest that both thrombocytopenia and platelet transfusions may be risk factors for hematoma expansion in ICH. Further study is needed to clarify the independent contributions of thrombocytopenia and platelet transfusions toward hematoma expansion and clinical outcome. Data access statement: Data available upon reasonable request.