Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) significantly impact patient morbidity, mortality, and healthcare utilization (Global Initiative for Chronic Obstructive Lung Disease [GOLD] 2024 Report.^[1] While common triggers include infections, a notable proportion (up to 30%) of AECOPD cases lack a clear etiology, posing a significant diagnostic challenge.^[2]

Growing evidence points to the crucial, yet often underdiagnosed, role of pulmonary embolism (PE) in AECOPD. COPD patients are inherently prone to venous thromboembolism (VTE) due to systemic inflammation, immobility, and polycythemia, making COPD an independent risk factor for PE.^[3] Recent meta-analyses indicate a considerably higher prevalence of PE in AECOPD, with pooled estimates ranging from 12.72% to 23.57%. Studies on unexplained AECOPD even report PE prevalence as high as 25-29.6% These figures are substantially higher than in the general population, demanding increased clinical suspicion.^[4]

The diagnostic difficulty arises from the significant overlap in clinical presentation between PE and AECOPD. Symptoms like acute dyspnea, cough, and chest pain are common to both, often masking PE and leading to delayed or missed diagnoses.^[5] This is further complicated by limitations of conventional tools; for example, D-dimer levels, while useful, can be non- specifically elevated in AECOPD, reducing their diagnostic specificity. The prognostic implications of a missed PE during AECOPD are severe, leading to increased mortality, longer hospital stays, and a higher risk of recurrence.^[6]

Despite increasing awareness, the precise incidence of PE during AECOPD within our specific patient population, and the factors associated with its occurrence, require further prospective investigation. A thorough understanding of this incidence is vital for refining local diagnostic pathways, optimizing patient care, and ultimately improving outcomes for AECOPD patients. Therefore, this prospective study aims to determine the incidence of pulmonary embolism in patients experiencing acute exacerbations of chronic obstructive pulmonary disease at our institution.

RATIONALE OF THE STUDY

Chronic Obstructive Pulmonary Disease (COPD) remains a leading cause of global morbidity and mortality. Acute exacerbations of COPD (AECOPD) are critical episodes characterized by acute respiratory deterioration, with a significant proportion of COPD-related deaths occurring during these events. The shared symptomatology between AECOPD (e.g., dyspnea, cough) and acute pulmonary embolism (PE) often leads to PE being overlooked, resulting in delayed or missed diagnoses. Furthermore, patients with COPD possess inherent risk factors for PE, including systemic inflammation, immobility, and polycythemia. This predisposition, coupled with the diagnostic challenge, contributes to higher mortality and morbidity in COPD patients who develop PE. Despite increasing recognition of this association, the precise incidence of PE during AECOPD and the specific clinical characteristics of these patients remain insufficiently elucidated. This knowledge gap underscores the urgent need for dedicated research to improve timely diagnosis and optimize management strategies.

AIM & OBJECTIVES

Aim

The primary aim of this study is to determine the incidence of pulmonary embolism during COPD exacerbations and to describe the clinical aspects in COPD patients diagnosed with PE.

Objectives

• To determine the incidence of pulmonary embolism during COPD
• To describe the clinical aspects in COPD patients diagnosed with pulmonary

Study Design

The current Prospective study was conducted for a period of 12 Months on 50 Patients

Study Population

This prospective study will include patients presenting to the outpatient clinic or admitted as inpatients in the Department of Respiratory Medicine, Government Medical College Hospital, Coimbatore. Patient selection will be based on strict adherence to the following inclusion and exclusion criteria:

Inclusion Criteria

• Patients able to provide informed consent.

• Both male and female patients.

• Patients with a confirmed diagnosis of COPD presenting with an acute

Exclusion Criteria

• Pregnant

• Patients living with Human Immunodeficiency Virus (HIV).

• Patients unwilling to participate in the

• Patients with a history of hypersensitivity to iodinated contrast

• Patients with a diagnosis of chronic renal

• Patients with a diagnosis of congestive heart

• Patients currently on anticoagulant

Methodology

Informed Consent: Written informed consent will be obtained from all eligible patients prior to their participation in the study.

COPD Diagnosis and Exacerbation Confirmation: Confirmation of COPD diagnosis will be established through a comprehensive review of medical history, previous medical records, chest X-ray findings, and spirometry results. The severity of COPD will be determined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. An acute exacerbation will be defined as a worsening of the patient's respiratory symptoms beyond their usual day-to- day variation.

Clinical Evaluation

Medical History: Chronic exposure to risk factors (e.g., smoking), persistent cough, progressive dyspnea, and recurrent respiratory infections.

Previous Medical Records: Documentation aligning with the above history and prior spirometry results.

Chest X-ray: May show signs of hyperinflation or emphysema, but primarily used to rule out other conditions.

Spirometry: Post-bronchodilator FEV1/FVC ratio < 0.70 is essential for confirming persistent airflow limitation

Pulmonary Embolism Risk Assessment: The Wells Score for Pulmonary Embolism will be applied to all enrolled patients to assess their pre-test probability for PE.

Confirmation of Pulmonary Embolism: CT Pulmonary Angiography (CTPA) will be performed on all patients with a Wells Score of >3. The diagnosis and incidence of pulmonary embolism will be confirmed based on the findings from the CTPA

Among 50 patients admitted with COPD exacerbations CTPA was performed in 18 patients with Wells clinical prediction score >=3. 6 patients out of the 18 had pulmonary embolism on CTPA, which accounts for 12% of the total study population.

Graph 1

P value: —0.053

There is no statistically significant association between Age Group and Pulmonary Embolism in our sample.

Graph 2

P-Value: —0.767

There is no statistically significant association between Gender & Pulmonary Embolism in our sample group. This suggests that, based on this Patient group, gender alone is not a significant

Graph 3

P-Value: -0.0037

There is a statistically significant association between GOLD Severity and CTPA Pulmonary Embolism in our study. This suggests that patients with more severe GOLD classifications (Severe and Very Severe) are significantly more likely to have pulmonary embolism compared to those with mild or moderate GOLD classifications in our sample population.

Graph 4

P value: ≈0.0000147

There is a statistically significant association between Wells Score Category (specifically, having a Wells Score >3) and Pulmonary Embolism in our study group. This strongly suggests that patients with a Wells score greater than 3 are significantly more likely to have pulmonary embolism compared to those with a Wells score of 3 or less in this study population which is consistent with the clinical utility of the Wells score for PE.

Graph 5

The t-test revealed a highly statistically significant difference in mean CRP levels between the two groups. Patients diagnosed with pulmonary embolism had significantly higher average CRP levels (>20) compared to those without PE, suggesting that elevated CRP is associated with the presence of PE in our study population.

Graph 6

This prospective study aimed to determine the incidence of pulmonary embolism (PE) during acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and to identify associated clinical factors. The findings revealed a PE incidence of 12% among the 50 enrolled patients, which aligns with previous metaanalyses reporting prevalence rates of 12.72% to 23.57% in similar populations (Yang et al., 2024)^[2]. This underscores the importance of considering PE as a potential etiology in AECOPD, particularly given the overlapping symptomatology that often leads to under diagnosis (Couturaud et al., 2021).^[5] The study identified significant associations between PE and severe GOLD classifications, elevated Wells Scores (>3), and higher CRP levels. Patients with severe or very severe COPD (GOLD classifications) were more likely to develop PE (p=0.0037), corroborating findings by Akpinar et al. (2024), who highlighted the role of systemic inflammation and immobility in increasing VTE risk in advanced COPD. The Wells Score demonstrated strong predictive utility, with a statistically significant association between scores >3 and PE (p≤0.0000147), consistent with its established clinical value (Kural et al., 2015)^[6]. Elevated CRP levels in PE-positive patients (mean 29.83 vs. 14.0; p<0.0001) further support the link between systemic inflammation and PE risk, as noted in prior research (Tillie- Leblond et al., 2023)^[4]. Notably, age and gender did not significantly predict PE in this cohort, contrasting with some studies that identified older age as a risk factor (Yang et al., 2024)^[2]. This discrepancy may reflect the relatively small sample size or homogeneous risk profiles in our population. The lack of gender association aligns with recent meta-analyses suggesting that COPD-related PE risk is driven more by disease severity and inflammation than by demographic factors.

Among patients admitted the acute exacerbation of chronic pulmonary disease, pulmonary embolism was detected in 12% of patients which is higher when compared with general population. Based on the analysis of our study population, the presence of Pulmonary Embolism appears to be significant with more severe GOLD classifications (Severe & Very Severe), Wells Scores greater than 3, and higher CRP levels. Age & Gender however, did not show a statistically significant association with PE in this sample group.

1. 1.      Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Prevention, Diagnosis and Management of COPD: 2024 Report. 2024. Available from: https://goldcopd.org/2024-gold-report/
2. 2.      Li M, Wang W, Liu M, et al. The prevalence and risk factors of pulmonary embolism in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis. Thromb J 2025;23(1):42.
3. 3.      Li J, Qu S, Liu R, et al. Prevalence and risk factors of pulmonary embolism in COPD patients complicated with secondary polycythemia. Int J Chron Obstruct Pulmon Dis 2024;19:2371-85.
4. 4.      Gourdain L, Tillie-Leblond I, Marcos-Martin E. Chronic obstructive pulmonary disease exacerbation purulence status and its association with pulmonary embolism. ERJ Open Res 2025;11(2):00202-2025.
5. 5.      Couturaud F, Sanchez O, Pernod G, et al. Diagnostic strategy for pulmonary embolism in patients with acute exacerbation of chronic obstructive pulmonary disease: a systematic review. Respiration. 2021;100(1):14-22.
6. Kural A, Cindil E, Atam B, et al. Prevalence and predictors of pulmonary embolism in patients with acute exacerbation of chronic obstructive pulmonary disease. J Bras Pneumol. 2015;41(4):307-13.