LAUSR

Purpose: To compare the characteristics and outcomes of severely injured trauma patients with or without preinjury stroke. Methods: A retrospective matched cohort study was conducted using data from the Japan Trauma Databank (JTDB), a Japan-nationwide hospital-based trauma registry from the year of 2003 to 2017. Adult (>15 years old) trauma patients were selected from the database and subjected to the within-cluster propensity-score matching. Patients with or without preinjury stroke were matched on 1:1 basis with the balancing of preinjury confounders consisted of fixed effect confounders (age and preinjury comorbidities except for stroke) and random effect confounders (sex, year of injury and hospital). The mechanism, anatomical distribution and severity of injury under the definition of the Abbreviated Injury Scale and hospital mortality was compared across the patients with or without preinjury stroke. Association between prior stroke and hospital mortality was also assessed by the quasi Poisson regression model doubly-adjusted for confounders included in the propensity score estimation and the trauma severity. Results: Of 294,274 patients registered in JTDB, 13,532 and 254,670 trauma patients did and did not complicate with preinjury stroke were selected as the study participants, respectively. Within-cluster propensity score matching extracted 13,212 patients each with or without preinjury stroke whose preinjury characteristics were adequately balanced across the groups. Fall on the ground was the most popular mechanism of injury and significantly higher in the group with preinjury stroke (75.9% versus 64.4%, risk ratio [RR] 1.18 95%CI [1.14, 1.21]). The severe injuries in head (34.1% versus 31.4%, RR 1.09 96%CI [1.04, 1.14]) pelvis and lower extremities (42.9% versus 39.8%, RR 1.08 95%CI [1.04, 1.12]) were relatively frequent in the stroke survivors, in contrast, those in chest, abdomen, and spine were relatively infrequent in the stroke survivors. Adjusted hospital mortality was similar in patients with or without prior stroke (RR 1.00 95%CI [0.91, 1.09]). Conclusion: Severely injured trauma patients with preinjury stroke were associated with frequent fall and possibly fall-related injuries on the head, hip and lower extremities.