Blend sign as a prognostic factor for spontaneous intracerebral hemorrhage: A systematic review and meta-analysis

Background and objectives: The blend sign (BS) is a known predictor of hemorrhage expansion. However, its prognostic value remains unclear. Therefore, we aimed to compare functional and mortality outcomes between intracerebral hemorrhage (ICH) patients with and without BS. Methods: We searched PubMed, EMBASE, Web of Science, and Cochrane Library for studies comparing patients with and without BS who underwent either conservative treatment or surgical evacuation for spontaneous ICH. Outcomes were functional status, hemorrhage expansion, mortality, and initial hematoma volume. Statistical analysis was performed using R software (version 4.4.0), and heterogeneity was assessed with I-2 statistics. Results: We included 13 studies with a total of 8685 patients, of whom 5131 (59.08 %) were male. The mean age was 64.64 +/- 4.92 years, and the follow-up period ranged from 30 to 360 days. Poor neurological outcomes (OR 1.71, 95 % CI: 1.23 & horbar;2.37, p < 0.01, I-2 = 84.2 %) and hemorrhage expansion (OR 2.11, 95 % CI: 1.36 & horbar;3.26, p < 0.01, I-2 = 42 %) were significantly higher in patients with BS. However, the overall mortality rate (OR 1.56, 95 % CI: 0.95 & horbar;2.58, p = 0.08, I-2 = 0 %) was not statistically different between groups. Furthermore, no significant differences were found in initial hematoma volume (MD 1.26 mL, 95 % CI: -9.94-12.46, p = 0.83, I-2 = 92 %). Conclusion: Patients with blend sign are associated with higher rates of poor neurological outcomes and hemorrhage expansion. Therefore, BS is a clear and easily identifiable finding that, based on our results, can improve patient management and treatment selection.