Rate of incident polyneuropathy in patients with transthyretin amyloid cardiomyopathy

Background: In patients with transthyretin amyloid cardiomyopathy (ATTR-CM), amyloid can be deposited in the peripheral nerves, causing polyneuropathy (PN). We evaluated the rate of incident PN diagnosis among ATTR-CM patients. Methods: This study utilized German claims data from January 2016–December 2023. We included adults newly diagnosed with ATTR-CM without a prior history of PN based upon International Classification of Diseases-Tenth Revision-German Modification (ICD-10-GM) diagnosis codes and coding for diagnostic testing. We identified incident PN using both a narrow (ATTR-PN-related) and broad (also including non-ATTR-specific polyneuropathies) set of ICD-10-GM codes. Incidence rates/100 person-years (PYs) with 95% confidence intervals (CIs) were calculated. Results: We identified 309 newly diagnosed patients with ATTR-CM free of PN. During a median follow-up of 430 days (Q1 = 175, Q3 = 936) the rate of broadly defined incident PN was 10.8 cases/100PYs (7.9–14.3), declining to 2.4 cases/100PYs (1.2–4.1) when the narrow ATTR-related PN definition was used. Conclusions: In German routine care, the incidence of ATTR-related PN in patients with ATTR-CM was 2.4/100PYs, rising to 10.8/100PYs under a broad symptom-based definition. Although ATTR-related PN was infrequently identified in ATTR-CM, PN and ATTR-CM may coincide.