# Outcomes of combined carbazochrome sodium sulfonate plus tranexamic acid therapy versus tranexamic acid monotherapy in traumatic brain injury: a retrospective cohort study in Japan

## TL;DR

This study compared the effectiveness of combining carbazochrome sodium sulfonate with tranexamic acid versus using tranexamic acid alone in treating traumatic brain injury in Japan.

## Contribution

The study provides new evidence on the clinical outcomes of combined therapy versus monotherapy for traumatic brain injury in a large Japanese cohort.

## Key findings

- Combined therapy did not significantly reduce 28-day in-hospital mortality compared to monotherapy.
- Subgroup analysis showed a significant reduction in 7-day mortality for unarousable patients receiving combined therapy.
- Routine use of carbazochrome sodium sulfonate may not be recommended based on the overall findings.

## Abstract

Traumatic brain injury (TBI) is a major public health concern associated with substantial morbidity and mortality. In Japan, carbazochrome sodium sulfonate (CSS) is widely used, often in combination with tranexamic acid (TXA), for the management of various types of bleeding; however, studies on the effectiveness of CSS in TBI are scarce. Therefore, this study aimed to investigate the association between the use of CSS plus TXA versus TXA alone and the clinical outcomes in patients with TBI.

This observational study was conducted using data retrieved from the Japanese Diagnosis Procedure Combination database between July 2010 and March 2022. We enrolled adult patients aged ≥ 16 years diagnosed with TBI who received TXA on the day of admission. Patients with chronic subdural hematoma, suspected TBI diagnosis, or severe extracranial trauma were excluded. The exposure was CSS plus TXA administration on the day of admission, with TXA monotherapy assigned as the control. The primary outcome was 28-day in-hospital mortality, and the secondary outcomes were 7-day in-hospital mortality, overall in-hospital mortality, consciousness at discharge, and length of hospital stay. We used propensity-score overlap weighting to balance patient characteristics between the groups.

This study included 150,026 patients. Of these, 17,212 (11.5%) received TXA alone, and 132,814 (88.5%) received CSS plus TXA. After propensity score overlap weighting, the primary outcome did not differ significantly between the TXA-only and CSS plus TXA groups (11.7% vs. 11.9%; risk difference, 0.1%; 95% CI − 0.4 to 0.7%). The secondary outcomes were also comparable between the two groups. However, the subgroup analysis restricted to unarousable patients (Japan Coma Scale 100–300) revealed a significant reduction in the 7-day mortality in the CSS plus TXA group.

Combined treatment with CSS and TXA was not associated with better clinical outcomes in terms of in-hospital mortality, consciousness at discharge, or length of hospital stay in hospitalized adult patients with TBI compared with TXA therapy alone. Routine use of CSS may not be recommended.

The online version contains supplementary material available at 10.1186/s40560-026-00855-w.