title: Interstitial lung diseases in Saudi Arabia: A single-center study.
abstract: BACKGROUND
  There are relatively few epidemiological studies on interstitial lung disease (ILD) worldwide.
  
  
  OBJECTIVE
  To report the incident cases of ILD and compare our data with reports from other populations.
  
  
  METHODS
  Newly diagnosed ILDs were prospectively collected at a single tertiary care hospital from January 2008 to December 2011. Detailed demographic and clinical data were collected at the time of diagnosis, along with the results from diagnostic procedures, including high-resolution computed tomography (HRCT), serological tests, bronchoalveolar lavage (BAL), transbronchial lung biopsy, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and surgical lung biopsy.
  
  
  RESULTS
  A total of 330 cases were included. The mean age was 55.4 ± 14.9 years. There was a slight predominance of females (202; 61.2%), and the male-to-female ratio was 1:1.37. The most frequent disease was connective tissue disease (CTD)-associated ILD (34.8%), followed by idiopathic pulmonary fibrosis (IPF) (23.3%), sarcoidosis (20%), and hypersensitivity pneumonitis (6.3%). Non-classifiable ILD was present in 1.8% of the total ILD cases. HRCT was performed in 97.3% of the cases, BAL in 17.5%, transbronchial lung biopsy in 21.8%, EBUS-TBNA in 4.5%, and surgical lung biopsy in 22.7% (38.6% of which were performed among the idiopathic interstitial pneumonia cases).
  
  
  CONCLUSIONS
  CTD-ILD and IPF were the most frequently observed ILDs in this Saudi Arabian population. Similarities and differences were found with respect to the previous reports from other countries.
authors: Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors: Esam H
authors: EH
authors: Alhamad
keywords: Connective tissue disease; epidemiology; hypersensitivity pneumonitis; idiopathic pulmonary fibrosis; interstitial lung disease; lung dominant; sarcoidosis