Abstract 11748: A Retrospective Observational Study Exploring Real-World Diagnostic Workup of Patients With Wild-Type Transthyretin Amyloid Cardiomyopathy and/or Light Chain Amyloidosis

Abstract

Introduction: Light chain (AL) and transthyretin amyloidosis are the most common forms of cardiac amyloidosis. Despite having similar presentation, the prognosis and treatment pathways are distinct, placing importance on accurate diagnosis. Aim: Assess the real-world diagnostic workup for AL in patients with AL, wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM), or both (AL+ATTRwt-CM). Methods: A retrospective study of Optum EHRs from Jan 2019-Dec 2021. Diagnostic workups in the 24 months prior to first diagnosis (index date) were assessed in mutually exclusive patient cohorts (aged ≥18 years) with AL (ICD10: E85.81 not E85.82), ATTRwt-CM (ICD10: E85.82 not E85.81), or AL+ATTRwt-CM (both ICD10 codes). Results: Of 49,466,996 patients in the database, 996, 526, and 31 met criteria for the AL, ATTRwt-CM, and AL+ATTRwt-CM cohorts, respectively ( Table ). Notable proportions of patients had no relevant workups (40%, 24%, and 23%) or no AL workups (40%, 29%, and 23%). Across cohorts, 54% (AL), 35% (ATTRwt-CM), and 61% (AL+ATTRwt-CM) received a workup for AL only, and >60% had 1-3 types of AL workup. Among patients tested with the serum-free AL assay (n=681), serum (n=460), or urine (n=286) immunofixation (IF) methods, ≥60% were in the AL cohort; ≤36% were in the ATTRwt-CM cohort and ≤4% in the AL+ATTRwt-CM cohort ( Figure ). Conclusions: In Optum EHRs, >20% of patients diagnosed with ATTRwt-CM or AL+ATTRwt-CM, and 40% with AL, had no relevant workups. Due to clinical urgency, it is critical to rule out AL in patients with cardiac amyloidosis using the AL assay or IF. These findings highlight the need for better diagnostic pathways for patients with suspected AL or ATTRwt-CM.