Corticosteroid Use and In‐Hospital Mortality in Patients With Brain Abscess: A Target Trial Emulation

PURPOSE: Corticosteroids are sometimes administered to patients with severe brain edema associated with brain abscess. However, no studies have used methods that appropriately account for time-varying covariates and immortal time to evaluate the impact of intravenous corticosteroid use on in-hospital mortality. Therefore, we aimed to address these limitations and estimate the impact on in-hospital mortality using a target trial emulation framework. METHODS: We identified patients admitted with brain abscess, not caused by head trauma or neurosurgical interventions, from two large-scale hospital-based databases in Japan between 2014 and 2024. We compared two treatment strategies: Strategy 1 was initiation of intravenous dexamethasone or betamethasone administration within 7 days after admission and continuing for at least 3 consecutive days; Strategy 2 was no intravenous corticosteroid use throughout hospitalization. Using a clone-censor-weight approach, we estimated the 60-day in-hospital mortality. RESULTS: A total of 627 patients met the eligibility criteria. Overall, 34 patients (5.4%) died within 60 days. The estimated total effect of treatment strategy on 60-day all-cause in-hospital death was 4.8% (95% CI, 1.1-9.2) for Strategy 1, and 4.6% (95% CI, 2.9-6.6) for Strategy 2, corresponding to a risk ratio of 1.04 (95% CI, 0.26-2.08) and risk difference of 0.2% (95% CI, -3.3 to 4.3). CONCLUSIONS: No clear difference in 60-day in-hospital mortality between the two treatment strategies; however, the wide confidence intervals indicate that clinically important benefit or harm could not be excluded. This study's framework may guide future studies using more granular data.