Polyneuropathy Assessment and Treatment Patterns in Patients with Hereditary Transthyretin Amyloidosis

INTRODUCTION: Hereditary transthyretin amyloidosis (hATTR) manifests as cardiomyopathy and/or polyneuropathy. Polyneuropathy may be suspected for a variety of reasons, but the clinical evidence supporting that impression varies. We used International Classification of Diseases, Tenth Revision (ICD-10) coding to broadly capture patients thought to have polyneuropathy in a V142I-predominant cohort and examined what clinical documentation actually supported the diagnosis and whether documentation level influences treatment selection. METHODS: Retrospective chart review of 54 patients identified by co-occurring ICD-10 codes for transthyretin amyloidosis and polyneuropathy at a major academic medical center, with pathogenic TTR variant confirmation. Polyneuropathy codes were then classified by the level of clinical evidence supporting the diagnosis. Treatment with TTR stabilizers and gene silencers was assessed. RESULTS: Of 54 patients (90.7% non-Hispanic Black, 87.0% V142I), 51 (94.4%) had confirmed cardiac involvement with 40/42 eligible (95.2%) receiving stabilizers. Sixteen patients (29.6%) received gene silencers, with 11 receiving both concurrently. Clinical evidence supporting the polyneuropathy code was identified in 43 patients (79.6%): ancillary testing confirmation in 18 (33.3%), provider documentation without ancillary testing in 14 (25.9%), and symptoms only in 11 (20.4%). The remaining 11 (20.4%) had insufficient documentation to support the code. Gene silencer use was highest among those with ancillary testing (50.0%) versus symptoms only (18.2%). CONCLUSION: Among patients with hATTR coded for polyneuropathy, only 33.3% had ancillary testing confirmation. Gene silencer use tracked with documentation quality rather than the presence of a code alone. These findings highlight the gap between administrative coding and clinical documentation and support standardized neurological assessment in hATTR.