Burden of wild-type transthyretin amyloid cardiomyopathy hospitalizations
A Del Debbio, C ColemanAbstract
Background
Transthyretin amyloid cardiomyopathy (ATTR-CM) occurs when amyloid fibrils derived from misfolded transthyretin monomers deposit into myocardium, resulting in stiff ventricles, cardiomyopathy, and heart failure (HF). Wild-type ATTR-CM (wtATTR-CM) accounts for ~70–80% of all cases and is associated with a high frequency of hospitalization. We sought to assess length of stay (LOS), total treatment costs, and inpatient mortality associated with hospitalizations for wtATTR-CM.
Methods
We used the National Inpatient Sample (NIS) to evaluate ATTR-CM inpatient hospitalizations from the years 2019-2022. NIS data is a 20% randomized sampling of all discharges from United States (US) hospitals taking part in the Healthcare Utilization Project (HCUP) and is representative of >97% of all inpatient hospital discharges. We included hospitalizations for adults ≥50 years of age with a primary diagnosis code for HF and an accompanying code for wtATTR-CM (E85.4 or E85.82) or a primary code for wtATTR-CM with a code for HF. We exclude patients with multiple myeloma, monoclonal gammopathy of undetermined significance, light chain amyloidosis, cerebral amyloid angiopathy, end stage renal disease/dialysis, or stem cell, heart or liver transplant. To create a nationally representative cohort, we used survey-specific analysis methods to weight patients while simultaneously accounting for clustering, stratification and the potential for sampling bias in the NIS. We performed descriptive analysis of outcomes on the weighted set of hospitalizations, including LOS, total hospital costs (in 2024 US$), and all-cause inpatient mortality. Results were reported as proportions or mean values with 95% confidence intervals (CIs).
Results
We found 17,875 ATTR-CM hospitalizations, with the incidence of wtATTR-CM hospitalizations steadily increasing from 2019-2022 (3.26, 3.41, 4.02 and 4.26 hospitalizations per 100,000 persons in the US ≥50 years old; p<0.001). The mean age of wtATTR-CM patients was 78.2 (77.8-78.5) years, and most were men (71.0%). The population was majority White (51.5%) or Black/African American (38.3%) (Table 1). Red flag comorbidities were common, with 78.3% of hospitalizations having at least one listed as a discharge diagnosis. These frequently included atrial arrhythmia (46.2%), conduction disorders (17.0%), degenerative joint disease (10.0%) and non-diabetic peripheral neuropathy (5.2%). The mean LOS was 7.5 days (7.2-7.7) and total treatment cost was $22,098 ($20,725-$23,472) per hospitalization (Table 2). Mortality occurred in 4.5% (3.9-5.2%) of hospitalizations.
Conclusion
In this nationally representative analysis of US inpatient hospitalizations from 2019–2022, the frequency of wtATTR-CM admissions rose over time. These hospitalizations were associated with substantial financial burden and mortality.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.