National data on prevalence of idiopathic pulmonary fibrosis and antifibrotic drug use in Finnish specialised care.

INTRODUCTION: The previous data concerning the prevalence of idiopathic pulmonary fibrosis (IPF) and the frequency of antifibrotic drug use in Finland were based on research registries and medical records whereas nationwide data on the number of patients with IPF in specialised care and those on antifibrotic treatment have not been published. METHODS: We made an information request to the Finnish National Hospital Discharge Register (Hilmo) covering the whole population of Finland to find out the annual numbers of patients with IPF treated in specialised care in 2016-2021. The numbers of the patients initiating and using pirfenidone and nintedanib were requested from the Social Insurance Institution of Finland (Kela) for the same time period. RESULTS: The estimated prevalence of IPF in specialised care was 36.0 per 100 000 in 2021, having increased since 2016. The number of antifibrotic drug users and their proportion of outpatients with IPF had also risen during the follow-up period. In 2021, 35% of the patients with IPF used pirfenidone or nintedanib. The number of inpatients treated in specialised care because of IPF had declined during 2016-2021. CONCLUSIONS: The prevalence of IPF was higher than expected in Finnish specialised care and had increased during the 6-year follow-up time. The increase in the number of patients with IPF using antifibrotic drugs might have diminished the need for IPF-related hospitalisations.