Prediction Model Effective for Community-Acquired Pneumonia in Those With Acute Asthma Exacerbations

This article was originally published by HCP Live^®. It has been lightly edited.

The use of a nomogram model was shown to be effective for prediction of community-acquired pneumonia (CAP) risk in hospitalized individuals with acute asthma exacerbations (AEs), according to recent findings from a retrospective study.¹ This study was designed to assess the clinical characteristics of acute AEs among those with CAP and to work toward a prediction model for CAP for those who have been hospitalized with such exacerbations.

Hospital surgery corridor | Image Credit: VILevi - stock.adobe.com

This research was viewed as invaluable, given that previous research shows pneumonia to be an independent risk factor for mortality among those hospitalized for asthma exacerbations and due to the varied prevalence of CAP in different studies.²

“We identified some of the clinical characteristics of adult AE patients with CAP,” wrote the researchers of the study. “We developed a prediction model to evaluate the CAP risk in adults with AEs.”

The research team conducted a retrospective examination of the records of patients treated at Beijing Luhe Hospital at Capital Medical University, gathering them between December 2017 and August 2021. All of the study subjects had diagnoses of AEs, specifically bronchial asthma, following Global Initiative for Asthma (GINA) diagnostic criteria.

AEs, as defined by the team’s criteria, involve sudden symptoms among patients, such as shortness of breath, wheezing, coughs, tightness in the chest, or a sharp worsening of existing symptoms, often requiring treatment changes. The investigators noted that the severity of such exacerbations was separated into mild to moderate, severe, or life-threatening based on the guidelines used in the study.

Inclusion criteria were subjects being 18 years or older and hospitalized for AEs. Exclusion criteria a hospital discharge within 24 hours with incomplete information, age younger than 18, pregnancy, having pulmonary vasculitis, having HIV, or being on immunosuppressive therapy.

The investigators used Lasso regression and multivariate logistic regression methods to point out the most successful predictors, and crafted their predictive nomogram utilizing these key predictors.

For internal validation of the nomogram model, the research team implemented the bootstrap technique. They sought to assess the nomogram's quality of performance by utilizing metrics such as the calibration curve, area under the receiver operating characteristic curve (AUC), and the decision curve analysis (DCA).

Overall, the study population encompassed 308 participants who had been admitted to the hospital for AEs. Twenty-one percent of these individuals were shown to have had CAP.

The research team noted that several elements were independently linked with CAP in the group: higher levels of fibrinogen, previous utilization of systemic corticosteroids, increased C-reactive protein levels, higher white blood cell count, observed existence of fever, and early-onset asthma.

The nomogram was shown to have predictive accuracy for CAP, with an AUC of 0.813 (95% CI, 0.753-0.872), and internal validation confirmed the model’s reliability, with a concordance index of 0.794.

The investigators also found that the calibration curve in their findings showed strong alignment with the study’s diagonal reference line. Additionally, their DCA indicated that the nomogram's clinical utility was shown to be the highest when the threshold probability of CAP in study subjects ranged from 3% to 89%.

Overall, the investigators reported there were distinctive clinical characteristics observed in this group, and the co-occurrence of such characteristics were shown to be relatively common.

“Using the nomogram, clinicians can determine the risk of CAP in patients hospitalized with an AE,” wrote the researchers. “With this prediction model, we can accurately predict the risk of CAP in patients with acute AE and play a role in early screening and diagnosis of CAP. This has an important role in guiding the use of antimicrobial drugs in patients with acute AEs.”

References

1. Duan, Y, Nafeisa, D, Lian, M, et al. Development of a nomogram to estimate the risk of community-acquired pneumonia in adults with acute asthma exacerbations. Clin Respir J. Published online October 4, 2023. doi:10.1111/crj.13706

2. Chang YL, Ko HK, Lu MS, et al. Independent risk factors for death in patients admitted for asthma exacerbation in Taiwan. NPJ Prim Care Respir Med. 2020;30(1):7. doi:10.1038/s41533-020-0164-4