# Impact of preoperative anemia on postoperative rate of severe complications and short-term clinical outcomes after retroperitoneal tumor resection

## TL;DR

Preoperative anemia increases the risk of severe complications and longer hospital stays after retroperitoneal tumor surgery.

## Contribution

Identifies preoperative anemia as an independent risk factor for postoperative complications and prolonged recovery in retroperitoneal tumor resection patients.

## Key findings

- Anemia group had higher rates of severe postoperative complications and longer ICU and hospital stays.
- Preoperative anemia was independently linked to prolonged mechanical ventilation and hospitalization.
- Anemia did not significantly affect 24-hour or 30-day postoperative mortality.

## Abstract

To investigate the impact of preoperative anemia incidence of severe complications and short-term clinical outcomes in patients undergoing retroperitoneal tumor resection.

We performed a retrospective cohort study, enrolling patients with retroperitoneal tumors who received resection at Peking University International Hospital from January 2015 to December 2023. Patient baseline data were collected, and the following outcome measures were recorded:​

• The primary outcome measure was the grade of postoperative complications;

•The secondary outcome measures included duration of mechanical ventilation, length of ICU stay, postoperative hospital stay, total hospital stay, postoperative 24-hour mortality, and postoperative 30-day mortality.​

Patients were divided into an anemia group and a non-anemia group according to the World Health Organization (WHO) criteria for anemia to analyze the effect of preoperative anemia on the aforementioned indicators.

A total of 1968 patients were included in this study, among whom 1100 (465 males and 635 females) had preoperative anemia, with an incidence rate of 55.9%. Statistically significant differences were noted between the two groups in terms of gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) physical status classification, and number of previous surgeries (all P < 0.05). Specifically, the anemia group exhibited a higher proportion of female patients, older age, lower BMI, a higher percentage of patients with ASA class III or IV, more patients with two or more previous surgeries, longer operation duration, and longer anesthesia duration compared with the non-anemia group.

Compared to the non-anemia group, the anemia group had a higher incidence of severe postoperative complications, along with significantly prolonged duration of mechanical ventilation, length of ICU stay, postoperative hospital stay, and total hospital stay. In the entire cohort, 4 patients (0.2%) died within 24 hours postoperatively, and 20 patients (1.0%) died within 30 days postoperatively.

Multivariate analysis, after adjusting for confounding factors including gender, age, and BMI, revealed that patients in the preoperative anemia group had a significantly increased risk of severe postoperative complications, as well as significantly prolonged duration of mechanical ventilation, ICU stay, postoperative hospital stay, and total hospital stay. Preoperative anemia was not correlated with mortality at 24 hours or 30 days after surgery.

Preoperative anemia is an independent risk factor for increased incidence of severe postoperative complications, as well as prolonged duration of mechanical ventilation, length of ICU stay, total hospital stay, and postoperative hospital stay in patients undergoing retroperitoneal tumor resection. Proactive management of preoperative anemia is critical for reducing postoperative complications and enhancing clinical outcomes in patients undergoing retroperitoneal tumor resection, thereby offering valuable insights for optimizing perioperative care in this population.

The online version contains supplementary material available at 10.1186/s12871-025-03573-2.