Prognostic impact of 18F-FDG PET and MRI-proven cardiac involvement in pulmonary sarcoidosis: a single center long-term cohort study

Background: Sarcoidosis is a systemic granulomatous disease, often affecting the lungs, with a generally favourable prognosis. However, some patients experience progressive disease, and cardiac involvement may worsen outcomes. Data on the clinical course and causes of death in pulmonary sarcoidosis (PS), especially with coexisting cardiac sarcoidosis (CS), remain limited. Methods: We retrospectively analysed patients with histologically confirmed PS. Baseline evaluations included chest X-ray and computed tomography, pulmonary function test, and echocardiography. CS was diagnosed using ¹⁸ F-fluorodeoxyglucose positron emission tomography and cardiac magnetic resonance imaging. Results: A total of 513 patients met the study criteria. The 3-, 5-, and 10-year survival rates were 98.2%, 97.0%, and 94.6%, respectively (median follow-up: 6.7 years). CS was diagnosed in 48 patients (9.4%), and survival was poorer in those with CS. Multivariate analysis identified CS as an independent predictor of poor prognosis (age-adjusted hazard ratio 3.55, 95% confidence interval 1.18–10.6). During follow-up, 21 patients (4.6%) died. Malignancy was the leading cause of death (48%), followed by cardiac death (14%) and respiratory failure (14%). Conclusions: Our PS cohort exhibited favourable outcomes, whereas CS was an independent prognostic factor. Comprehensive assessment for CS, as well as for lung involvement and malignant disease, is warranted for better outcomes in PS.