Risk Factors for Progression of Conservatively Managed Acute Traumatic Subdural Hematoma: A Systematic Review and Meta-Analysis

BACKGROUND: Conservatively managed posttraumatic acute subdural hematoma (SDH) can present with progression of the size of the hematoma with increased mass effect, necessitating delayed surgery. The factors contributing to this progression remain largely unknown. METHODS: A comprehensive search of the PubMed, Embase, and Scopus databases was performed to retrieve case control studies, retrospective cohort studies, and prospective studies with retrospective evaluation of risk factors until August 2, 2020. The different risk factors that were evaluated in the studies were compiled and the results were analyzed to arrive at a conclusion. RESULTS: A total of 7 studies were included in the systematic review and 6 were included in the analysis, with an aggregate of 679 patients. The following factors were found to have a relation with progression of acute SDH: age (odds ratio, 7.12; 95% confidence interval [CI], 2.52-11.72), use of antiplatelet drugs (odds ratio, 1.89; 95% CI, 1.18-2.77), use of anticoagulants (odds ratio, 3.09; 95% CI, 1.21-7.88), thickness of SDH (odds ratio, 4.13; 95% CI, 3.29-4.97), midline shift (odds ratio, 1.86; 95% CI, 0.69-3.03), hypertension (odds ratio, 2.22; 95% CI, 1.25-3.96) and ischemic heart disease (odds ratio, 3.32; 95% CI, 1.63-6.76). CONCLUSIONS: The results of this analysis showed that patients with the risk factors outlined are at higher risk of developing symptomatic chronic SDH after conservatively managed traumatic acute SDH compared with those without them. It is therefore necessary to provide more intensive follow-up for these patients to avoid an adverse outcome.