Assessment of Disease Burden Among Japanese Patients With Pulmonary Sarcoidosis: A Questionnaire-Based Study.

INTRODUCTION: Sarcoidosis is a systemic granulomatous disease that can form lesions in almost all organs and most commonly affects the lung. It often causes systemic symptoms such as generalized pain and fatigue, leading to reduced health-related quality of life (HRQoL). Although oral corticosteroids (OCS) are commonly used to manage sarcoidosis, they are associated with side effects and reduced HRQoL. In Japan, data on patient-reported outcomes remain limited. METHODS: This study assessed the disease burden in 158 Japanese patients with pulmonary sarcoidosis, recruited through a sarcoidosis patients' association, using a mailed questionnaire that included three patient-reported outcome measures: the King's Sarcoidosis Questionnaire (KSQ), Fatigue Assessment Scale (FAS), and Small Fiber Neuropathy Screening List (SFNSL). RESULTS: The mean age of patients was 68.4 years, and 85.4% were women. The median KSQ General Health Status score was 54.3, indicating a reduced HRQoL. Fatigue was prevalent, with 72.3% of patients scoring ≥22 on the FAS. Small fiber neuropathy (SFN) was suspected in 79.7% of patients with SFNSL scores ≥11. Patients receiving higher doses of OCS (n = 40) had significantly lower KSQ medication scores compared with those receiving lower doses of OCS (median 61.7 vs. 80.9, p = 0.001), suggesting a higher treatment burden. Additionally, OCS users exhibited a higher prevalence of extreme fatigue (FAS ≥35, 26% vs. 14%, p = 0.030) and suspected SFN (SFNSL ≥11, 90% vs. 70%, p < 0.001). CONCLUSION: These findings quantitatively demonstrate the burden of systemic symptoms, particularly fatigue and symptoms associated with SFN, in Japanese patients with pulmonary sarcoidosis, with the present study being the first to evaluate KSQ scores in Japan. Even though this study could not establish causality due to its cross-sectional nature, the results underscore the importance of regularly monitoring and managing fatigue and symptoms associated with SFN in patients undergoing treatment with OCS. Such insights may support clinical decision-making and could contribute to optimizing management while minimizing HRQoL impairment.