# The Predictive Value of Machine Learning for Postoperative Delirium in Cardiac Surgery: Systematic Review and Meta-Analysis

## TL;DR

This study reviews and analyzes how well machine learning can predict postoperative delirium after heart surgery, showing promising but still limited results.

## Contribution

A systematic review and meta-analysis of ML-based tools for predicting postoperative delirium in cardiac surgery patients.

## Key findings

- ML models achieved a c-index of 0.805, sensitivity of 0.72, and specificity of 0.78 in predicting delirium.
- Logistic regression was the most common modeling method, with a c-index of 0.773 in validation datasets.
- The study highlights the need for more robust, multicenter research to improve ML-based delirium prediction tools.

## Abstract

Postoperative delirium (POD) following cardiac surgery is a severe complication, and early identification of delirium risk remains a challenge in clinical practice. While machine learning (ML) has garnered increasing attention in health care applications, effective early prediction tools remain limited in current clinical practice. Recent investigations have explored the effectiveness of ML-based methods for identifying the risk of POD in patients undergoing cardiac surgery. However, more evidence is required to validate the feasibility of these methods.

This study aims to ascertain the performance of ML in identifying the risk of POD following cardiac surgery, providing evidence for the development or updating of future ML-based assessment tools.

A comprehensive literature search was conducted across 4 databases—PubMed, the Cochrane Library, Embase, and Web of Science—through August 30, 2024, to identify studies investigating individual POD risk prediction using ML approaches and nomograms. The risk of bias of the models in the included studies was assessed leveraging the Prediction Model Bias Risk Assessment Tool. Subgroup analyses were performed based on datasets, validation methods, study types, risk of bias, and model types.

The analysis incorporated 28 original studies comprising 80,143 patients undergoing cardiac surgery, of whom 6326 developed POD. Meta-analysis revealed that, in validation datasets, the c-index, sensitivity, and specificity for delirium prediction reached 0.805 (95% CI 0.759‐0.852), 0.72 (95% CI 0.65‐0.79), and 0.78 (95% CI 0.71‐0.83), respectively. Logistic regression was the primary modeling method. In validation datasets, the c-index, sensitivity, and specificity reached 0.773 (95% CI 0.724‐0.823), 0.73 (95% CI 0.64‐0.80), and 0.70 (95% CI 0.65‐0.74), respectively.

ML-based prediction tools for POD following cardiac surgery demonstrate promising performance. However, the limited number of studies and validation approaches necessitate cautious interpretation of these findings. Future multicenter studies are warranted to develop more robust ML-based prediction tools, enabling precise risk stratification and targeted preventive interventions for POD.