Background: Pulmonary function tests (PFT) are recommended in initial sarcoidosis evaluation and during follow-up. Cardiopulmonary exercise test (CPET) characterizes functional impairment and it is a valid tool in selected patients. ⁶⁷Ga scintigraphy and 18F-FDG PET/CT nuclear imaging identify signs of active sarcoidosis inflammation.

Aims: To investigate how CPET and PFT data relate to disease severity (Scadding stage) and to nuclear imaging signs of disease activity.

Methods: We collected PFT and CPET retrospective data from 48 sarcoidosis patients and 10 controls. Nuclear imaging data were also collected in a subset of 40 patients. First, we correlated individual CPET/PFT parameters to Scadding stage and nuclear imaging data. Then, we constructed multiple regression models to determine which variable subsets were the best predictors of Scadding stage and disease activity.

Results: The majority of CPET and PFT single parameters were significantly correlated with patient stage (Fig1a) while few correlated with disease activity (Fig1c). Nevertheless, multiple regression models were able to significantly predict both disease stage (Fig1b, r²=0.46) and activity (Fig1d, r²= 0.42), whilst highlighting CPET cardiovascular parameters as the best overall predictors.

Conclusions: CPET could complement PFT for sarcoidosis monitoring and both may help detect signs of active inflammation