Spectrum of diffuse parenchymal lung diseases at a tertiary care center in India

Abstract

Background: The frequency, incidence and prevalence of interstitial lung diseases (ILDs) have been mainly reported from the developed countries. The incidence of ILDs in countries of the Asia-Pacific region is unclear. Herein, we describe the incidence, prevalence and distribution of various ILDs from a developing country in this region. Method: We analyzed data of consecutive subjects (>12 years of age) with ILDs from a single tertiary care center. The following information was obtained: demographic and clinical details, findings on HRCT chest, spirometry, histopathological findings, and other ancillary investigations. The diagnosis of ILD was made by a multidisciplinary team in accordance with the American Thoracic Society/European Respiratory Society criteria. Result: A total of 651 subjects (mean age, 50.2 years; 49.3% women) were enrolled over 18 months. Sarcoidosis (43.3%), idiopathic pulmonary fibrosis (IPF, 21.2%), connective tissue disease-related ILDs (12.6%), hypersensitivity pneumonitis (9.8%), and non-IPF idiopathic interstitial pneumonias (8.9%) were the most common ILDs. A histopathological specimen was obtained in 50.5% of the subjects yielding a histologically confirmed diagnosis in 41.9%. The best estimates of the crude annual incidence and prevalence were 9.5 and 22.9 per 100,000 population, respectively. The spectrum of ILDs was not significantly different between incident and prevalent cases (p=0.86). Conclusion: There is considerable occurrence of ILDs in India. The incidence and prevalence are similar as those reported from European countries and the United States. The spectrum of ILDs was like previous reports from developed countries, albeit with subtle differences.