Prognostic impact of leukocytosis in intracerebral hemorrhage: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND: Intracerebral hemorrhage (ICH) is correlated with high rate of death and poor outcome. Leukocytes participate in secondary brain injury in ICH. It is still not clear that whether leukocytosis can predict outcome in ICH. This study was performed to summarize that current evidences about the association between baseline leukocytosis and outcome in ICH patients in a systematic review and meta-analysis. METHODS: Published studies were searched in 5 databases. Original studies about association between baseline leukocytosis and outcome in ICH were included. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were achieved to evaluate the association between leukocytosis and prognosis. RESULTS: A total of 19 eligible studies with 6417 patients were analyzed in this study. Meta-analysis showed baseline leukocyte count increase was significantly associated with worse overall (OR = 1.13, 95% CI 1.05–1.21, P = .001), short-term (OR = 1.20, 95% CI 1.05–1.38, P = .009), and long-term functional outcome (OR = 1.12, 95% CI 1.04–1.20, P = .004). Baseline leukocytosis defined by cut-off values had significant association with worse overall functional outcome (OR = 1.95, 95% CI 1.01–3.76, P = .046). Baseline leukocyte count increase was significantly associated with higher overall (OR = 1.10, 95% CI 1.02–1.18, P = .011) and long-term mortality (OR = 1.12, 95% CI 1.03–1.22, P = .007). Baseline leukocytosis defined by cut-off values was significantly associated with higher overall (OR = 1.67, 95% CI 1.23–2.27, P = .001) and short-term mortality (OR = 1.74, 95% CI 1.12–2.70, P = .014). CONCLUSION: Baseline leukocytosis could be helpful in predicting prognosis in ICH patients. However, its prognostic value should be verified by further studies.