# Clinical characteristics and outcomes of overt gastrointestinal bleeding in children undergoing haploidentical hematopoietic stem cell transplantation: a single-center retrospective analysis

## TL;DR

This study examines gastrointestinal bleeding in children after a specific type of stem cell transplant, finding it is common and linked to worse outcomes.

## Contribution

The study identifies risk factors for overt gastrointestinal bleeding in pediatric haploidentical stem cell transplant recipients.

## Key findings

- Overt gastrointestinal bleeding occurred in 25.2% of pediatric haplo-HSCT patients.
- Grade III–IV gut aGvHD, TMA, and CMV viremia are significant risk factors for overt GIB.
- Overt GIB is associated with reduced overall survival and increased non-relapse mortality.

## Abstract

Overt gastrointestinal bleeding (GIB) is a potentially serious and life-threatening condition in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, relatively little information is available regarding overt GIB in children.

To assess the prevalence, clinical patterns, and outcomes of overt GIB in children undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT).

A total of 123 consecutive patients with malignant or non-malignant blood disorders who received haplo-HSCT were reviewed in our hospital between October 2017 and October 2022. Overt GIB was determined as hematemesis, melena or hematochezia. Continuous variables were compared by Mann Whitney U test. Categorical parameters were compared by the χ2 test or Fisher’s exact test. Kaplan-Meier curves and log-rank tests were used to assess overall survival (OS), non-relapse mortality (NRM) and relapse. Univariate and multivariate analyses were performed to identify potential risk factors of overt GIB development.

The median follow-up was 26.3 (range,1.7–74.8) months. Overt GIB occurred in 31 patients (25.2% incidence), with a median time elapsed after haplo-HSCT of 376 days (range, 58–1275 days). Compared with the non-GIB group, patients with overt GIB had reduced OS and increased NRM. In multivariate analysis, grade III–IV gut acute graft versus-host disease (aGvHD), thrombotic microangiopathy (TMA) and cytomegalovirus (CMV) viremia were significant risk factors for the occurrence of overt GIB after haplo-HSCT.

Overt GIB is a frequent complication after haplo-HSCT in pediatric patients, and associated with worse survival. Grade III–IV gut aGvHD, TMA and CMV viremia were associated with its development.

The online version contains supplementary material available at 10.1186/s12887-024-04950-5.