Understanding Predictors of Response to Repository Corticotropin Injection Treatment Among Patients With Advanced Symptomatic Sarcoidosis

Background: Sarcoidosis, an inflammatory systemic granulomatous disease, affects multiple organs and has a diverse clinical course. Repository corticotropin injection (RCI) is an effective treatment for advanced symptomatic sarcoidosis. Since sarcoidosis affects patients differently, treatment response may vary by patient demographic, clinical, and treatment-related characteristics and physician specialty. However, there is a paucity of literature regarding predictors of sarcoidosis treatment response. Objectives: This study investigated predictors of response to RCI treatment. Methods: Post-hoc analysis was conducted using data from a previously published retrospective cross-sectional chart review study among symptomatic sarcoidosis patients ≥18 years of age previously treated with RCI. Outcome improvement 3 months post-RCI treatment was based on the clinician's subjective evaluation and analyzed using adjusted logistic regression. The most influential predictors for each outcome were based on statistical significance (P<.05) and the strength of the relationship assessed by the standardized β coefficients. Results: The top predictors of outcome improvements were as follows. Global health assessment: (1) improvement in current health status influenced by complete RCI compliance, moderate overall symptom severity, and presence of extrapulmonary sites; and (2) improvement in overall symptoms influenced by age, shorter duration since sarcoidosis diagnosis, and complete RCI compliance. Clinical outcomes: (1) lung function improvement influenced by mild weight loss, mild wheezing/coughing, and non-African American race; (2) reduction in pulmonary fibrosis influenced by moderate overall symptom severity, mild wheezing/coughing, and mild weight loss; and (3) reduction in inflammation influenced by physician specialty, completing a course of RCI treatment, and moderate-to-severe night sweats. Patient-related outcomes: (1) reduction in fatigue influenced by physician specialty and moderate-to-severe fatigue; and (2) improvement in quality-of-life influenced by shorter duration since sarcoidosis diagnosis, moderate-to-severe wheezing/coughing, and complete RCI compliance. Corticosteroid discontinuation/reduction was influenced by physician specialty, moderate-to-severe shortness of breath, and comedication use before RCI. Conclusions: RCI may be a better treatment option for patients with more severe disease, primarily those presenting with symptoms. Complete compliance with RCI treatment may improve patients' health and quality of life. Understanding factors that influence RCI effectiveness across different treatment outcomes in real-world clinical practice is important for designing optimal sarcoidosis treatment strategies.