Cardiovascular events in patients diagnosed with light chain amyloidosis in the USA: a real-world analysis utilizing electronic health records

Background Light chain (AL) amyloidosis is a rare disease characterized by the deposition of misfolded immunoglobulin light chains, often in the heart, and is associated with increased risk of mortality and cardiovascular (CV) events. Purpose This study estimates the incidence of CV events in AL amyloidosis patients in the USA. Methods A retrospective analysis was conducted using de-identified patient records from USA Optum's Clinical Electronic Health Record (EHR) database. Adults with AL amyloidosis were identified based on ≥2 diagnosis codes (ICD-10-CM code E85.81) or positive mentions of the disease in the physician’s notes (≥30 days apart). Patients with clinical data at least 12 months pre-index event (defined as the date of AL amyloidosis diagnosis during the identification period: Jan 01, 2017-Mar 31, 2021) were included. All cases with transthyretin amyloidosis (ATTR) ICD-10 codes were excluded provided evidence of AL-specific treatment was not found. AL-relevant CV events (e.g., heart failure) and interventions (e.g., pacemaker) were captured between the index date, the end of the study period (Mar31, 2022), or death. Incidence and event rates were calculated for cardiac events and CV interventions of interest. Results A total of 1859 AL amyloidosis patients were included in the study (mean age of 66.9 years at the index date and 53.9% male). Over a mean duration of follow-up of 2.1 years (maximum 5.9 years and SD, 1.4), 1291 (69.4%) and 382 (20.5%) patients experienced any CV event or any CV intervention, respectively. Post index date, the incidence rates (IR) of new and recurrent + new events/interventions per 1000 person-years (PYs) were 221/63 and 618/90, respectively. The highest CV event rates per 1000 PYs were conduction disorder/arrhythmias (283), heart failure (239), and cardiomyopathy (188), followed by valvular dysfunction (157), coronary insufficiency (77), syncope (57), and stroke (23). The highest rate per 1000 PYs of CV interventions were pacemaker (29), cardiac defibrillation (23), and angioplasty/bypass (7). The incidence of heart transplant was 2 events per 1000 PYs. Conclusions Despite recent therapeutic advances that target the underlying plasma cell dyscrasia, we still observed a substantial occurrence of CV events and interventions in AL amyloidosis patients. Studying CV events further is essential for identifying effective therapeutic strategies to improve the management of AL amyloidosis.