# Association of mean corpuscular volume with 28-day mortality in sepsis patients: A retrospective cohort study using eICU data

## TL;DR

This study found that higher mean corpuscular volume (MCV) is linked to increased 28-day mortality in sepsis patients, with a key threshold at 83 fl.

## Contribution

The study identifies a non-linear relationship between MCV and sepsis mortality, highlighting a critical threshold for clinical awareness.

## Key findings

- Each 1 fl increase in MCV was associated with a 1.11-fold higher odds of 28-day mortality after adjusting for confounders.
- A non-linear positive correlation was observed, with a significant increase in mortality risk for MCV levels below 83 fl.
- The inflection point for MCV was identified at 83 fl, beyond which the mortality risk increased more sharply.

## Abstract

The issue of mortality due to sepsis remains a significant concern in the field of medicine. Previous researches have demonstrated an association between mean corpuscular volume (MCV) and mortality from a range of diseases. The objective of this study was to investigate the relationship between MCV and the risk of mortality from sepsis in a large multicentre cohort.

A retrospective cohort study was conducted using data from the eICU Collaborative Research Database from 2014–2015. MCV was determined within the initial 24 hours of ICU admission, with patients subsequently classified into quartiles based on their MCV levels. Multivariate regression models were employed to investigate the correlation between MCV and 28-day mortality, with adjustments made for potential confounding factors such as age, sex, body mass index, vital signs and comorbidities. To evaluate the dose-response relationship between MCV and 28-day mortality in patients with sepsis, smoothed curve fitting and threshold effects analysis were utilised.

A total of 9,415 patients with sepsis were included in the study and the 28-day ICU mortality rate of the sepsis patients was 9.38% (883/9415). After adjusting for confounding variables, it was found that the odds ratio (OR) for 28-day mortality was 1.11 (95% CI 1.01, 1.23, P=0.04) increased followed by each 1 fl increase in MCV. The smoothed fitted curves demonstrated a nonlinear positive correlation between MCV and 28-day mortality. The inflection point for the level of MCV was 83 fl. At MCV <83 fl, there was a significant increase in the risk of 28-day mortality with each 1 fl increase in MCV (OR 1.10, 95% CI 1.02, 1.17, P=0.004).

There is a non-linear positive correlation between MCV and 28-day risk of death in patients with sepsis. Clinicians should be aware of changes in this indicator, especially in patients with high MCV levels.