Epidemiology of diffuse interstitial lung disease in Reunion Island

Rational Interstitial lung disease (ILD) encompasses many pathologies, and its epidemiology may vary locally according to demographic, ethnic or environmental factors. Objective The aim of our study is to describe the epidemiology of chronic ILD in Reunion Island, and to identify local specificities related to these factors to better guide their management. Method Patients were retrospectively recruited from Novembre 2018 to November 2019 by pulmonologists and internists in Reunion Island. The primary objective was to estimate the incidence and prevalence of chronic ILD in Reunion Island. The secondary objective was to describe the characteristics of the patients. Data was collected retrospectively, at the time of inclusion defined by the date of the first chest CT scan indicative of ILD, from the computerized medical file. Results Connective tissue diseases (CTDs) was the leading cause of ILD (36% of cases), whereas sarcoidosis accounted for 4%. Idiopathic pulmonary fibrosis accounted for 16% of ILDs. The overall ILD prevalence was 41.16 per 100,000 inhabitants, with an incidence of 6.89 per 100,000 inhabitants per year. Cryobiopsy was the most common lung sampling method. Conclusions The distribution of ILDs varied in contrast to most published cohorts with the predominance of CTDs associated ILDs (36%) and sarcoidosis representing only 4% of ILDs. The crude prevalence and incidence of ILDs was lower compared to mainland France, although likely partially due to lower hospital coverage. Prospective work is needed to explain this epidemiology and to identify specific environmental factors for ILD in Reunion Island. Clinical trial number Not applicable.