Clinical Profile and Predictors of Venous Thrombotic Events in Patients with Chronic Respiratory Diseases - An Observational Study

Background and Objective: Growing evidence suggests an increased risk of venous thromboembolism (VTE) in chronic respiratory disease (CRD) patients. Persistent lung inflammation, repeated hospitalization, and associated comorbidities render patients prone to VTE. Considering the limited data, we intended to determine the clinical profile and risk factors of VTE in CRD. Methods: A retrospective case-control study was conducted at the Department of Pulmonary Medicine in a tertiary respiratory care center. The medical records of CRD patients from January 2020 to March 2023 were reviewed and data were collected. Confirmed cases with VTE (n = 50) using Doppler and computed tomography pulmonary angiogram (CTPA) and matched controls (n = 50) without VTE were included in the study. Clinical and radiological profiles of these patients, including age, sex, presence of comorbidities, duration of illness, severity of CRD, treatment details, chest radiograph, electrocardiogram, CBC, CRP, and D-dimer levels, were recorded. Predictors for VTE were assessed using univariate and multivariate analyses. Results: VTE was found more commonly in middle-aged patients and those with TOPD and COPD. Univariate analysis showed high pulse rate, low oxygen saturation (SpO2), higher diastolic blood pressure, higher mMRC grade of breathlessness, evidence of cor pulmonale on 2D echo, elevated WBC count, and CRP and D-dimer levels to be the predictors of VTE. In the multivariate analysis, low SpO2, higher mMRC grade of breathlessness, and elevated CRP and D-dimer levels were found to be independent predictors for VTE. We found 72% and 80% sensitivity and specificity for serum C-reactive protein at 58mg/dl and 84% and 100% sensitivity and specificity for D-dimer values at 560 ng/LFEU, respectively. Conclusion: VTE was found to be more common in tuberculosis-associated obstructive pulmonary disease (TOPD) than COPD at our centre. Low SpO2, greater severity of breathlessness, and elevated serum CRP and D-dimer levels were considered independent predictors of VTE in CRD. In CRD patients presenting with clinical worsening, evaluation for VTE in the presence of these risk factors can be useful in reducing morbidity and mortality.