Diagnostic Efficacy of Frequent Acute Exacerbations Investigated in Patients With COPD

A mix of imaging and clinical characteristics was able to identify the frequent acute exacerbations phenotype in patients with chronic obstructive pulmonary disease (COPD), according to a new study.

COPD is a common disease with high morbidity, with acute exacerbations resulting in worsening of respiratory symptoms. This study, which aimed to identify frequent acute exacerbations in patients with COPD using imaging and clinical characteristics, found that patients with frequent exacerbations had a larger low attenuation area less than –950 Hu (LAA-950), and tended to have more severe visual subtypes, suggesting new treatment guidance for patients who have already received a COPD diagnosis.

“Multivariate binary logistic regression indicated that clinical indicators combined with imaging characteristics played an important role in predicting frequent exacerbations of patients who were initially diagnosed with COPD,” wrote the researchers of this study. “Increases in LAA-950 and worsening of visual subtypes symbolized more frequent exacerbations.”

The results of this retrospective study were published in Respiratory Medicine.

This study initially recruited 261 patients whose COPD was diagnosed using pulmonary function tests (PFTs) from January 2020 to May 2022 in Shanghai, China. Patient data included age, sex, symptoms upon admission, smoking status, height, weight, and PFT indicators. Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) were measured by severity: mild, moderate, and severe.

Patients with comorbid lung cancer, who had received lung surgery, who had bronchiectasis, and who were missing information were excluded, leaving 201 patients in this study. Of these patients, 112 were placed into a nonfrequent exacerbation group and 89 patients were placed in a frequent exacerbation group. For this analysis, frequent AECOPD was split into 2 definitions:

• Moderate: AECOPD > 2
• Severe: AECOPD > 1

All patients received an inspiratory high-resolution CT examination and PFTs, which evaluated forced expiratory volume at 1 second (FEV₁); forced vital capacity (FVC); FEV₁/FVC; percentage of FEV₁, the predicated value (FEV₁ pred); residual volume; and total lung volume.

The researchers followed patients for up to 1 year after their initial diagnosis and divided them into the frequent and nonfrequent exacerbation groups.

Patients with frequent exacerbations had a greater risk of larger LAA-950 than those with nonfrequent exacerbations (odds ratio [OR], 1.322; 95% CI, 1.19-1.47; P < .001). Frequent COPD exacerbations were associated with worsening visual subtypes, age, smoking status, body mass index, FEV₁ pred, and LAA-950.

Age older than 65 years, being a former or current smoker, and having a BMI ≤ 23.39, an FEV₁ pred ≤ 50.10, and LAA-950 > 20.30 were associated with frequent acute exacerbations.

Lastly, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC-ROC) were used to predict frequent acute exacerbations and total prediction probability. The researchers found that the frequent acute exacerbation group had the highest AUC-ROC, of 0.907 (Z = 19.76; 95% CI, 0.86-0.94; P < .001), while the prediction probability in the nonfrequent acute exacerbation group was an AUC of 0.895 (Z = 17.92; 95% CI, 0.84-0.92; P < .001).

The researchers acknowledged that this study has some limitations, including that patients with mild exacerbations may be heterogeneous in their symptoms and tolerance. Additionally, some symptoms may have been extensions of COPD, making distinguishing between symptoms difficult.

However, despite these limitations, the researchers were able to demonstrate a strong association between risk factors of frequent acute exacerbations in patients with COPD by using imaging and clinical characteristics.

“In conclusion, we found that, in patients with frequent exacerbations of COPD, the LAA-950 was larger, and the visual subtypes tended to the more severe phenotype,” wrote the researchers. “Combining imaging and basic clinical characteristics reached good diagnostic efficacy in predicting frequent acute exacerbations of COPD. This may provide a new treatment direction for patients who are initially diagnosed with COPD.”

Reference

Zhu D, Dai H, Zhu H, et al. Identification of frequent acute exacerbations phenotype in COPD patients based on imaging and clinical characteristics. Respiratory Medicine. Published online February 8, 2023. doi:10.1016/j.rmed.2023.107150