High-Resolution CT Characterization of Radiologic Phenotypes among COPD Patients in Sindh, Pakistan

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide, particularly in low- and middle-income countries (LMICs), where environmental exposures and limited healthcare access exacerbate disease burden [1–3,4]. COPD exhibits marked structural and clinical heterogeneity, with emphysema and chronic bronchitis as its principal phenotypes. High-resolution computed tomography (HRCT) offers detailed visualization of structural lung changes, aiding phenotypic characterization and prognosis [10–13].
Objective: To characterize radiologic phenotypes of COPD among patients in Sindh, Pakistan, and examine their distribution across different age groups using HRCT in conjunction with clinical assessment, spirometry, and chest radiography.
Methods: A cross-sectional observational study was conducted at the Department of Respiratory Medicine, NRIGH, Sindh, Pakistan, enrolling 90 consecutive patients aged 35–75 years with confirmed COPD. Patients underwent detailed clinical evaluation, pulmonary function testing, chest radiography, and HRCT imaging. HRCT scans were analyzed to identify emphysema subtypes, small airway disease, and other structural abnormalities. 
Age-related differences in phenotypes were assessed using Z-tests for proportions.
Results: The mean age of participants was 54.8 years, with 75.6% aged 41–60 years. Predominant emphysema was observed in 56.7% of patients, chronic bronchitis in 36.7%, and mixed patterns in 6.6%. Chronic bronchitis was more frequent in patients ≤50 years, whereas emphysema predominated in those >50 years (p < 0.05). HRCT revealed centrilobular emphysema (46.7%), small airway disease (40.0%), panacinar (16.7%) and paraseptal emphysema (8.9%), with occasional ground-glass opacities, interstitial lung disease, and mass lesions. Spirometry confirmed persistent airflow limitation with minimal bronchodilator reversibility, and radiographic findings correlated with structural phenotypes.
Conclusion: COPD in this cohort demonstrates significant structural and phenotypic heterogeneity, with emphysema predominating in older adults and chronic bronchitis in younger patients. HRCT is a valuable adjunct to spirometry and radiography for accurate phenotypic characterization, early detection of comorbidities, and individualized management. These findings highlight the importance of imaging-based phenotyping to inform clinical decision-making in resource-limited LMIC settings.