• Sarcoidosis
• Clinical Epidemiology
• Respiratory Measurement

In sarcoidosis, any organ may be affected, and the majority of cases have pulmonary involvement. The disease course in pulmonary sarcoidosis varies considerably, from complete resolution to chronic disease and/or pulmonary fibrosis. The heterogeneity of sarcoidosis is a major challenge in treatment decision-making, and the hope is that subgrouping patients into phenotypes may help to provide the right care for the right patient. In this issue of Thorax, Sharp et al 1 provide evidence that sarcoidosis phenotypes, based on pulmonary function tests (PFTs), predict lung function decline over time. They found that individuals with a restrictive pulmonary phenotype had a greater 3-year loss in pulmonary function compared with those without impairment. Furthermore, black individuals had a less favourable course compared with white individuals who improved in pulmonary function over time.

The study by Sharp et al included longitudinal data with several years of follow-up, which is an improvement over previous studies which were based on cross-sectional data. Prognosis prediction in sarcoidosis is challenging due to the wide variation across patients, and many studies have not been replicated. Previous studies have examined different blood-based biomarkers, but it is still unclear whether these are reliable and useful to predict progression to fibrosis. Some more recent …