A meta-analysis to determine the effect of anticoagulation on mortality in patients with blunt head trauma

Introduction. Patients on warfarin are increasingly common in an ageing population. Previously published case series and cohort studies have resulted in conflicting conclusions with regard to the risk of fatal intracranial haemorrhage. The aim of this study was to undertake a meta-analysis in order to compare the mortality rate of anticoagulated head injured patients against the mortality rate of head injured patients not on coumarin anticoagulation. Methods. The databases Medline and EMBASE were searched via the ovid interface. The initial search strategy returned 364 results. A second search was performed using Pubmed to identify possible abstracts missed by the first search. Forty-seven full articles were reviewed if the abstract suggested that they were either case control studies or nested case control studies comparing the mortality rate of anticoagulated head injured patients against the mortality rate of head injured patients not on coumarin anticoagulation. Results. Eleven papers were identified, which met the criteria for the meta-analysis. Despite the heterogeneity between the studies (Q test: 27.421, 10 DF, P = 0.002), the fixed effects model may be the preferred model based on the fact that 10 out of the 11 studies had an odds ratio greater than one. The fixed effects model produced a common odds ratio for death in anticoagulated patients with blunt head trauma of 2.008 (95% CI 1.634-2.467). Conclusions. The results of this meta-analysis has shown that the cohort of patients who are anticoagulated and suffer blunt head trauma appear to have an increased risk of death compared to a similar cohort of head injured patients who are not anticoagulated.