Incidence of interstitial lung diseases in the south of Spain 1998-2000: the RENIA study

This study aims to describe the distribution of interstitial lung diseases (ILD) in the South of Spain. Methods: A prospective multicentre population-based registry was established in nine provinces in the south of Spain with a population of 6,848,243 during a 3-year period (1998–2000). The number of participant physicians was 36 among 29 public hospitals. The number of diagnoses recorded was 66, divided in eight categories and coded according to ICD-9. A consensus document was elaborated for the classification of diseases and their diagnostic criteria. The number of cases declared was analysed each 3 months and communicated to each one of the participants. Results: There were 744 cases of them registered with an annual incidence of 3.62 cases/100,000. 40.1% of diagnoses were biopsy confirmed. Men had a slightly higher incidence (4.18 cases/100,000/year) than women (3.07 cases/100,000/year). The most frequent diseases found were: idiopathic interstitial pneumonias (38.58%), ILD associated to systemic diseases (20.97%), and Sarcoidosis (11.69%). According to province distribution, most of the cases were grouped in an area between the provinces of Seville and Cordoba, which comprised more than 50% of cases. Conclusions: The study of the incidence of ILD depicts an intermediate situation from previous studies on the incidence and distribution of this group of diseases.