Subtype Distribution of Amyloidosis in the United States: Insights from an Electronic Health Records Database Analysis

Speaker(s)

Laires PA1, Zhang Y2, Manwani R3, Silva AM1, Catini J4, Thompson J4, Dozier M4, Yang F4
1Alexion–AstraZeneca Rare Disease, Barcelona, Barcelona, Spain, 2Cytel Canada Health Inc, Vancouver, BC, Canada, 3University College London Hospital, London, London, UK, 4Alexion– AstraZeneca Rare Disease, Boston, MA, USA

OBJECTIVES: This study investigated subtype distribution of amyloidosis, a rare disease, specifically light-chain amyloidosis (AL) and transthyretin amyloidosis (ATTR). The distribution of the two forms of ATTR, wild-type [ATTRwt] and variant [ATTRv], and its phenotypes was also evaluated.

METHODS: A cross-sectional analysis was conducted using an anonymized dataset from TriNetX Dataworks, USA Network, an electronic health records database of approximately 95 million patients from 57 USA healthcare organizations. Adults diagnosed with amyloidosis between 01/01/2021-12/31/2021 and with ≥2 records for amyloidosis ≥30 days apart were included. Subtypes and phenotypes of amyloidosis ascertained by ICD-10 coding system.

RESULTS: 5575 amyloidosis cases were analysed with 30% (N=1,671) and 4% (N=218) classified as AL and ATTR, respectively. Other types accounted for 44% of cases (N=2,433) and the remaining 22% (N=1,253) as unspecified amyloidosis. Within ATTR, ATTRwt and ATTRv constituted 45% (N=99) and 55% (N=119) of cases, respectively. Phenotypic manifestations of ATTR were as follows: cardiac-only 28% (N=60); neuropathic-only 36% (N=78); concomitant cardiac and neuropathic 16% (N=34). Among ATTRwt, phenotype was as follows: cardiac-only 52%; neuropathic-only 8%; concomitant cardiac and neuropathic 15%. Among ATTRv cases: cardiac-only 8%; neuropathic-only 59%, concomitant cardiac and neuropathic 16%.

CONCLUSIONS: Contemporary literature on epidemiology of amyloidosis is limited and inconsistent. Our results demonstrate that the commonest subtypes of amyloidosis (ATTR and AL) were surprisingly underrepresented, particularly ATTRwt. A likely cause for this discrepancy is that ICD-10 coding in amyloidosis does not reflect accepted clinical classification of amyloidosis which is based on precursor type and heredity. A single ICD-10 code can include numerous types of amyloidosis, and there is no specific code for ATTRv. Our findings reveal a pressing need for appropriate coding to reflect amyloidosis subtype classification in order to foster real-world research in amyloidosis, so that we may develop our understanding of this rare disease and improve treatment and outcomes.

Code

EPH251

Disease

Rare & Orphan Diseases