# Admission systemic immune-inflammatory index predicts long-term mortality in patients with acute ischemic stroke: a retrospective analysis of the MIMIC-III database

## TL;DR

A new inflammation-based index predicts long-term survival in stroke patients using hospital data.

## Contribution

This is the first study to show that the Aggregate Index of Systemic Inflammation (AISI) predicts stroke patient mortality over two years.

## Key findings

- High AISI levels correlate with 31% higher 90-day mortality in stroke patients.
- AISI above 5841.5 shows a gradual increase in mortality risk over two years.
- AISI is a promising predictor of long-term stroke outcomes.

## Abstract

The Aggregate Index of Systemic Inflammation (AISI) is a novel index based on platelets, neutrophils, and lymphocytes associated with the prognosis of patients with cancer and infectious diseases. However, its application in acute ischemic stroke (AIS) has rarely been reported. This study evaluated stroke prognosis using AISI by examining the relationship between levels of systemic immunoinflammatory indices at admission and patient outcomes at different times after onset.

This was a retrospective cohort study. The data from 1222 stroke patients were obtained from multiparameter intelligent monitoring in the Intensive Care III database (MIMIC-III). Cox proportional risk model was conducted to estimate the relation between AISI, all-cause mortality, and ischemic. The findings were further validated with restricted cubic spline (RCS) and subgroup analyses.

A total of 1222 patients with AIS were classified into tertiles based on AISI levels, tertile 1: low AISI, AISI levels less than 3881 (n = 408), tertile 2: medium AISI, AISI levels 3881 to 8354 (n = 408), and tertile 3: high AISI, AISI levels greater than 8354 (n = 407). After adjusting for multiple covariates, it was found that AISI was related to all-cause mortality in stroke patients. Patients with high AISI had a 31% increased risk of death after 90 days (HR = 1.31, 95% CI 1.03–1.67, P = 0.03) compared to patients with low AISI. Patients with high AISI had a 27% increased risk of death after 365 days (HR = 1.27, 95% CI 1.03–1.58, P = 0.029) than low AISI patients. Furthermore, compared with patients with low AISI, patients with high AISI had a 30% increased risk of death after two years (HR = 1.30, 95% CI 1.05–1.60, P = 0.014). During the 2-year follow-up period, the use of RCS showed that the mortality rate gradually increased with the increase of AISI value after 5841.5.

Systemic immunoinflammatory indices are related to long-term adverse outcomes in patients with AIS. Therefore, AISI is a promising inflammatory index for predicting the long-term prognosis of stroke.