Comparison of DLCO and Spirometry for Monitoring of Disease in Patients of ILD

Background: The relative utility of DLCO and spirometry in monitoring interstitial lung disease (ILD) progression remains debated. This study aimed to evaluate the correlation between these parameters and their relationship with disease progression. Methods: A cross-sectional study of 54 patients with confirmed ILD was conducted at M.M. Institute of Medical Sciences and Research. Spirometry, DLCO measurements, and HRCT were performed at baseline, 3 months, and 6 months. Clinical parameters, including dyspnea grade and 6-minute walk test, were assessed. Results: The study population comprised 22 males (40.7%) and 32 females (59.2%), with interstitial pneumonia (42.6%) and IPF (22.2%) as predominant diagnoses. Mean FVC% predicted declined from 54.33±13.37 to 51.05±13.02 over 6 months, while DLCO remained relatively stable (35.74±16.49 to 35.37±16.12). Strong correlation was observed between baseline DLCO and FVC values (κ=0.87). Patients with DLCO <70 showed significantly lower FVC% predicted compared to those with DLCO >70 (54.8±1.8 vs 80.9±1.6, p=0.001). Reticular pattern was the predominant radiological finding (57.41%). Conclusion: DLCO and spirometry provide complementary information in ILD monitoring, with FVC showing earlier changes over the 6-month period. The strong correlation between these parameters suggests their combined utility in assessing disease severity and progression.