Registration of interstitial lung diseases by 20 centres of respiratory medicine in Flanders.

AbstractWe report the results of a prospective registration of the prevalence of interstitial lung diseases by 20 centres of respiratory medicine in Flanders from January 1992 till July 1996. The 20 centres registered a total of 362 cases. Sarcoidosis (31% with inclusion of stage I, or 22% without stage I), idiopathic pulmonary fibrosis (20%), hypersensitivity pneumonitis (13%) and unclassified forms of interstitial lung diseases (9%) were the most often diagnosed diseases. The mean age of the patients was 52 ± 17 (SD) years, but ranged from 32 ± 10 years in histiocytosis X to 70 ± 13 years in drug induced interstitial lung diseases. The male to female ratio was 1.3 but ranged from 2.3 in interstitial lung diseases due to inhalation of inorganic materials to 0.8 in interstitial lung diseases due to connective tissue disease. The diagnosis was considered certain in 60%, probable in 30% and possible in 10%. In 50% of the cases the diagnosis was proven by biopsy and the most often used biopsy technique was t...