Organ involvement in newly diagnosed sarcoidosis patients in the Netherlands: The first large European multicentre prospective study

Background Clinical presentation and prevalence of organ involvement is highly variable in sarcoidosis and depends on ethnic, genetic and geographical factors. These data are not extensively studied in a Dutch population. Aim To determine the prevalence of organ involvement and the indication for systemic immunosuppressive therapy in newly diagnosed sarcoidosis patients in the Netherlands. Methods Two large Dutch teaching hospitals participated in this prospective cohort study. All adult patients with newly diagnosed sarcoidosis were prospectively included and a standardized work-up was performed. Organ involvement was defined using the WASOG instrument. Results Between 2015 and 2020, a total of 330 patients were included, 55% were male, mean age was 46 (SD 14) years. Most of them were white (76%). Pulmonary involvement including thoracic lymph node enlargement was present in 316 patients (96%). Pulmonary parenchymal disease was present in 156 patients (47%). Ten patients (3%) had radiological signs of pulmonary fibrosis. Cutaneous sarcoidosis was present in 74 patients (23%). Routine ophthalmological screening revealed uveitis in 29 patients (12%, n = 256)). Cardiac and neurosarcoidosis were diagnosed in respectively five (2%) and six patients (2%). Renal involvement was observed in 11 (3%) patients. Hypercalcaemia and hypercalciuria were observed in 29 (10%) and 48 (26%, n = 182) patients, respectively. Hepatic involvement was found in 6 patients (2%). In 30% of the patients, systemic immunosuppressive treatment was started at diagnosis. Conclusions High–risk organ involvement in sarcoidosis is uncommon at diagnosis. Indication for systemic immunosuppressive therapy was present in a minority of patients.