Posttraumatic Amnesia: A Systematic Review and Meta-Analysis. Proposal for a New Severity Classification

Background: Posttraumatic amnesia (PTA) duration is used to predict outcome after traumatic brain injury (TBI): however, no meta-analysis exists. Methods: A systematic review was performed following PRISMA reporting guidelines. The databases Scopus-1966, PubMed/MEDLINE, CINAHL, PsycINFO, and Embase were searched for relevant texts. Random effects meta-analysis derived pooled estimates of the odds ratio of outcomes of interest and sensitivity and specificity of PTA at different cutoffs, and subsequently a summary receiver operating curve was derived. PTA prediction of Glasgow Outcome Scale (GOS) and Glasgow Outcome Scale–Extended (GOSE) scores was assessed both qualitatively and quantitatively by pooled odds ratio regarding both a good outcome (GO: GOS-5 or GOSE-7/GOSE-8) and a severe disability outcome (SDO: GOS-3 or a GOSE-3/GOSE-4). Summary receiver operating curve analysis was performed in the prediction of composite of a moderate disability outcome (MDO: GOS-4 or GOSE-5/GOSE-6) and SDO. Results: Twenty-four studies were included in qualitative synthesis, and 9 (12,386 patients; males, 64%–84%) in meta-analysis. The odds of a GO and SDO were significantly different between PTA >56 days and PTA <7 days (P = 0.04 and P = 0.03). PTA