# Prediction of postoperative infections by strategic data imputation and explainable machine learning

## TL;DR

This study uses machine learning to predict postoperative infections more accurately by analyzing changes in lab values over time.

## Contribution

The novel approach integrates postoperative lab value kinetics with explainable machine learning to improve infection prediction.

## Key findings

- Infection prediction models using postoperative lab kinetics achieved a recall of 0.71, precision of 0.69, and ROC AUC of 0.83 by postoperative day 2.
- Dynamic modeling outperformed clinician-based decisions in detecting infections earlier.
- Previously unknown combinations of hepatic, renal, and bone marrow markers were found to predict infection risk.

## Abstract

Infections following healthcare-associated interventions drive patient morbidity and mortality, making early detection essential. Traditional predictive models utilize preoperative surgical characteristics. This study evaluated whether integrating postoperative laboratory values and their kinetics could improve outcome prediction.

91 794 surgical cases were extracted from electronic health records (EHR) and analyzed to predict bacterial infection as the endpoint. The endpoint was documented in the EHR as ICD-10 by a professional coding team. Variables were grouped as preoperative, intraoperative, or postoperative. Strategic imputation was used for postoperative missing laboratory values. Procedure-agnostic prediction models were built incorporating both static and kinetic properties of laboratory values.

The integration of kinetics of laboratory values into a machine learning predictor achieved a recall, precision and ROC AUC at postoperative day 2 of 0.71, 0.69, and 0.83, respectively. Moreover, infection detection outperformed clinician-based decision-making, as reflected by the postoperative timing of antibiotic administration. The analysis identified previously unknown, informative combinations of routine markers from hepatic, renal, and bone marrow functions that predict outcome.

Dynamic modelling of postoperative laboratory values enhanced the timeliness and accuracy of infection detection compared with static or preoperative-only models. The integration of explainable machine learning supports clinical interpretation and highlights the contribution of multiple organ systems to postoperative infection risk.

A surgery-independent workflow integrating time-series values from laboratory parameters to enhance baseline predictors of infection. This interpretable approach is generalizable across procedures and has the potential to optimize patient outcomes and resource use in surgical care.