Read Aloud the Text Content

This audio was created by Woord's Text to Speech service by content creators from all around the world.

Text Content or SSML code:

An increase in sarcoidosis incidence is supported by some longitudinal studies [7,26], whereas others find no change in incidence over time [8,27]. Byg et al. studied Danish patients with sarcoidosis identified in the DNPR from 1980 to 1994 and found a lower overall incidence of 7.2 per 100,000 per year [3]. Differences in study design between Byg et al. and the present study are noteworthy when evaluating this two-fold increase in incidence. Firstly, Byg. et al. included individuals younger than 18 years and given the rarity of sarcoidosis in children, this results in a relatively lower IP. Secondly, out-patient are recorded in the DNPR since 1995, and thus only included in the present study, contributing to a higher IP in the present study. Noteworthy, two methodological differences will tend to overestimate the IP by Byg et al. as compared to the present study. Firstly, no wash-out period was applied by Byg et al. before 1980 and secondly, cases were included upon their first visit. The present study included a wash-out period of three years, making the index-date of sarcoidosis highly likely to be the first-time diagnosis and cases were required to have at least two visits to reduce the risk of misclassification. Although the latter two methodological differences are likely to have lesser impact on the IP they are important contributors to the correctness of the IP estimate. The observed increase in incidence is particularly high in the nontreatment group, supporting the assumption that the increase in incidence is mainly due to an overall increase in diagnostic procedures, leading to more accidental findings of sarcoidosis (Supplementary 4). This is furthermore supported by the temporal coincidence of the introduction of fast-track (cancer) pathways and the marked increase in incidence from 2008 (Fig. 2). Conversely, the +MTX/AZA groups almost double in incidence during the 15-year study period; this may indicate an increased awareness of the need to initiate steroid-sparing therapies, rather than reflecting an actual increase in severe/chronic sarcoidosis (Supplementary 4).