(CCSP060) ASSOCIATIONS BETWEEN ANEMIA AND CLINICAL OUTCOMES IN CARDIAC AMYLOIDOSIS

Background: Light chain (AL) and transthyretin (ATTR) cardiac amyloidosis (CA) cause restrictive cardiomyopathy with progressive heart failure (HF). Although anemia is a common comorbidity in HF, associated with adverse outcomes, the prevalence, incidence, and outcomes of anemia associated with CA remain poorly understood.

METHODS AND RESULTS: We performed a retrospective cohort study of patients seen and followed in a dedicated Cardiac Amyloidosis Clinic between January 2010 and May 2022. Baseline demographic, clinical, laboratory, and imaging data were collected, as well as clinical outcomes. Factors associated with baseline and incident anemia were identified. Univariable and multivariable regression models were used to identify associations with clinical outcomes.

We identified 300 patients who were diagnosed with CA during the study period and followed for up to 5 years. Median follow up was 22.8 months in ATTR and 27.3 months in AL. Mean age was 71.3 years and 80.2% of patients were male. Amyloid type was AL in 81 patients (27.1%) and ATTR in 217 (72.8%). At baseline, mean left ventricular ejection fraction (LVEF) was 58.2%, mean glomerular filtration (GFR) rate was 59 mL/min/m2, and mean hemoglobin was 131 g/L. Mean values for mean corpuscular volume (MCV), ferritin, and serum iron were 92 fL, 199.9 ug/L, and 12.9 umol/L, respectively. Macrocytosis was seen in 11% of patients and microcytosis in 3.6% at baseline.

Anemia was present at baseline in 39% and developed in an additional 15% during follow up. Compared to those without baseline anemia, anemic patients had lower baseline GFR (53 vs. 62 mL/min/m2, p=0.0008), MCV (91 vs. 93 fL, p=0.06), and serum iron (11 vs. 14 umol/L, p=0.01). Among ATTR patients, anemic patients were more likely to report a history of HF than non-anemic patients (86% vs. 69%, p=0.007). Anemia was not associated with clinical outcomes in the overall cohort. In ATTR, anemia was associated with time to death (HR 2.0, p=0.01) and time to death or HF hospitalization (HR 1.8, p=0.02); however, when adjusted for age, ATTR stage, and baseline NYHA class, anemia was no longer associated with risk of either outcome.

Conclusion: Anemia is prevalent in CA patients, and associated with lower GFR, MCV and serum iron levels. Associations between anemia and outcomes in ATTR can be explained by coexisting variables, suggesting that anemia is a marker of more severe disease. Further investigation is needed to better understand mechanisms of anemia in ATTR versus AL patients.