# Red blood cell distribution width-to-albumin ratio and postoperative pleural effusion risk after gastrectomy for esophagogastric junction adenocarcinoma: a retrospective study

## TL;DR

This study shows that a higher red blood cell distribution width-to-albumin ratio before surgery increases the risk of pleural effusion after gastrectomy in patients with esophagogastric cancer.

## Contribution

RAR is identified as a novel, preoperative predictor of postoperative pleural effusion in Siewert type II/III adenocarcinoma patients.

## Key findings

- Elevated RAR is independently associated with increased postoperative pleural effusion risk (OR = 1.69).
- RAR demonstrates strong predictive capacity with an AUC of 0.796 for pleural effusion risk.
- Subgroup analysis confirms a significant association between RAR and pleural effusion in Siewert type II/III AEG patients.

## Abstract

Postoperative pleural effusions (PPE) are common complications following gastrectomy, particularly in patients diagnosed with Siewert type II/III esophagogastric cancer. The red blood cell distribution width-to-albumin ratio (RAR) is a marker indicative of systemic inflammation and nutritional status. This study investigates the association between preoperative RAR and the incidence of PPE in patients with Siewert type II/III adenocarcinoma of the esophagogastric junction (AEG) who have undergone gastrectomy.

A retrospective analysis was performed on data from 299 patients with Siewert type II/III AEG who underwent gastrectomy between January 2020 and December 2024. Logistic regression analysis was utilized to assess the relationship between RAR and PPE, while the receiver operating characteristic curve was employed to evaluate the predictive capability of RAR for PPE risk, with results expressed as the area under the curve (AUC).

PPE was diagnosed in 85 patients, representing 28.43% of the study cohort. After adjusting for relevant covariates, a positive association between the RAR and PPE following gastrectomy was observed (odds ratio [OR] = 1.69, 95% confidence interval [CI]: 1.22–2.34, P = 0.002). The incidence of PPE demonstrated a progressive increase across ascending RAR quartiles, with patients in the highest quartile experiencing a significantly increased risk of PPE compared to those in the lowest quartile (OR = 4.15, 95% CI: 1.28–13.45, P = 0.02). Furthermore, RAR exhibited a strong predictive capacity for PPE risk, as indicated by an AUC of 0.796. Subgroup analysis further confirmed a significant positive association between RAR and PPE. Stratified analysis revealed significant interactions between hemoglobin levels (P = 0.04) and the effect of RAR on PPE.

An elevated RAR is independently associated with an increased risk of PPE, suggesting its potential utility as a pragmatic, clinically feasible supplementary index for patients with Siewert type II/III AEG prior to undergoing gastrectomy. However, due to the study’s single-center, retrospective design and absence of external validation, further research with external cohorts is needed before RAR can be considered for widespread clinical implementation.