(P-007) Association Between the Use of Mood Stabilizers and Risk of Trauma Among Patients with Bipolar Disorder

Background: Patients with bipolar disorder (BPD) are often more aggressive and easily agitated, especially during mania, contributing to elevated risk of trauma which is one of the common reasons of presenting at the emergency room (ER). Earlier studies showed that mood stabilizers, such as lithium, antipsychotics and antiepileptics with mood stabilizing properties – valproate, lamotrigine and carbamazepine, can effectively reduce symptoms and prevent relapse. Therefore, we hypothesized that mood stabilizers might reduce risk of trauma related ER admissions by reducing agitation. However, scant studies were conducted to examine this association.

Objectives: To investigate the association between mood stabilizers and risk of trauma related ER admissions among patients with BPD

Methods: Design, Setting and Participants: We used a population-based electronic health records database from the Hong Kong Clinical Data Analysis and Reporting System to identify patients with BPD aged 18 or above who were treated with mood stabilizers including lithium, antipsychotics, antiepileptics (valproate, lamotrigine and carbamazepine only) between 2001 and 2019. Individuals who had at least one episodes of trauma related ER admissions were included in the analysis.
Main outcome measure: Relative incidence of trauma related ER admission during the time periods when patients were exposed to mood stabilizers compared to non-exposure periods.
Statistical analysis: Self-controlled case series study design

Results: Among 16537 patients with BPD who received at least one prescription of any of the mood stabilizers, 5953 of them had their first episode of trauma related ER admission during the study period. An increased rate of trauma related ER admissions was observed before the treatment of mood stabilizers was initiated, with an incidence risk ratio (IRR) of 4.33 (95% Confidence interval (CI) 3.66-5.12). The IRR was dropped to 1.37 (95% CI 1.19-1.57) during the first 30 days of treatment before returning to baseline levels during the subsequent treatment period with an IRR of 0.96 (95% CI 0.88-1.05). Then IRR was risen to 1.31 (95% CI 1.08-1.59) during the 30-days post-exposure period.

Conclusions: The incidence of trauma related ER admissions was much lower right after the treatment was initiated compared to the period prior the start of treatment, reflecting that this study supports our hypothesis. The observed increased risk of trauma related ER admissions in the period shortly after the treatment cessation implicated the importance that patients should not stop their medications abruptly without doctors’ advice.