Risk factors and establishment of a nomogram model for pulmonary arterial hypertension complicated by acute exacerbation of chronic obstructive pulmonary disease

Abstract

Objective: To identify risk factors for pulmonary arterial hypertension (PAH) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and develop a nomogram model to facilitate early clinical identification of high-risk patients and guide personalized treatment plans.

Methods: This retrospective study included 602 AECOPD patients treated at Zhoushan Women and Children's Hospital from June 2018 to May 2023. Patients were divided into two groups based on the presence or absence of PAH. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for AECOPD with PAH. A nomogram model was then established based on these factors. The Bootstrap self-sampling method was used to evaluate the predictive performance of the model. Indicators such as the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and consistency index (C-index) were calculated to evaluate the discrimination and calibration of the model.

Results: Among 602 AECOPD patients, 8.31% developed PAH. Compared with the non-PAH group, the PAH group exhibited a higher proportion of Chronic Obstructive Lung Disease (GOLD) grade IV, hypertension, and elevated neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Multivariate logistic regression analysis identified GOLD grade, hypertension, NLR, PLR, and NT-proBNP as independent risk factors for AECOPD-associated PAH. A nomogram prediction model was developed based on these variables. The model's AUC, sensitivity, and specificity in the training set were 0.906 (95% confidence interval (CI): 0.847-0.966), 0.850, and 0.862, respectively, and those in the validation set were 0.861 (95% CI: 0.715-0.932), 0.700, and 0.948, respectively. The C-index for the calibration curves of the model in both the training and validation sets was high (0.906 and 0.861, respectively). Decision curve analysis indicated a positive net benefit within a certain risk threshold.

Conclusion: PAH in AECOPD patients was associated with GOLD grade, hypertension, NLR, PLR, and NT-proBNP. The developed nomogram demonstrated strong predictive performance and clinical utility.

Keywords: Acute exacerbation of chronic obstructive pulmonary disease; exacerbation period; nomogram; prediction; pulmonary arterial hypertension; risk factors.

Figure 1

Receiver operating characteristic (ROC) curve analysis for each independent risk factor in predicting PAH in AECOPD. AECOPD: acute exacerbation of chronic obstructive pulmonary disease; PAH: pulmonary arterial hypertension; GOLD: the Global Initiative for Chronic Obstructive Lung Disease; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio; NT-proBNP: N-terminal pro-brain natriuretic peptide.

Figure 2

The nomogram prediction model based on risk factors. GOLD: the Global Initiative for Chronic Obstructive Lung Disease; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio; NT-proBNP: N-terminal pro-brain natriuretic peptide.

Figure 3

Receiver operating characteristic (ROC) curve analysis for the model’s predictive performance in training (A) and validation (B) sets. AUC: the area under the receiver operating characteristic curve; CI: confidence interval.

Figure 4

Calibration curve for the predictive model. A. Training set; B. Validation set.

Figure 5

Decision curve analysis for the predictive model. A. Training set; B. Validation set.