# A machine-learning model to identify concurrent vascular disease in symptomatic patients with chronic obstructive pulmonary disease

## TL;DR

This study developed a machine-learning model to detect vascular disease in COPD patients, improving diagnostic accuracy and reducing unnecessary interventions.

## Contribution

A novel Stacking machine-learning model was developed and validated for concurrent vascular disease detection in COPD patients.

## Key findings

- The Stacking model achieved an AUC of 0.867 with 79.4% accuracy in identifying vascular disease.
- The model demonstrated excellent calibration and net clinical benefit within a threshold probability range of 0.1–0.5.
- It could prevent 35% of unnecessary interventions while identifying 75% of high-risk patients.

## Abstract

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous syndrome often accompanied by vascular diseases that worsen prognosis and quality of life. This study aimed to develop a machine learning model to identify concurrent vascular diseases in symptomatic COPD patients.

We retrospectively analyzed data from 6,274 COPD patients treated between July 2010 and July 2018. Patients were randomly split into training and validation sets (7:3). After feature selection using LASSO regression, eight machine learning algorithms—including Logistic Regression, Random Forest, Gradient Boosting, Support Vector Machine, Neural Network, Convolutional Neural Network, AdaBoost, and Stacked Generalization (Stacking)—were applied to develop and validate predictive models. Performance was evaluated using AUC, calibration curves, and decision curve analysis (DCA).

The Stacking model achieved the highest AUC (0.867; 95% CI: 0.852–0.882), with 79.4% accuracy, 74.9% sensitivity, and 84.0% specificity. It also demonstrated excellent calibration and, on DCA, provided the highest net clinical benefit within the threshold probability range of 0.1–0.5. At a 0.2 threshold, the model could prevent approximately 35% of unnecessary interventions compared to a "treat-all" approach, while identifying about 75% of high-risk patients relative to a "treat-none" strategy.

The Stacking machine-learning model showed superior performance in identifying concurrent vascular disease among symptomatic COPD patients, offering strong discriminative ability, calibration, and clinical utility. It may serve as an effective decision-support tool to optimize diagnostic evaluation in this high-risk subgroup.