Natural history and survival rate of familial amyloidosis with polyneuropathy: A nationwide databank.

Objective: Hereditary amyloid transthyretin (ATTRv) amyloidosis with polyneuropathy, a rare autosomal-dominant disease, has gained attention in recent years owing to treatment improvements. However, epidemiological real-world mega database of nationwide natural history and survival rates, especially with the specific mutation of Ala97Ser, are limited.

Methods: Taiwan National Health Insurance Research Database contains data from over 23 million individuals; Among them, 175 ATTRv amyloidosis patients validated by rare disease registry were enrolled. Multivariable Cox proportional hazard analyses were applied to investigate the association between baseline characteristics and all-cause mortality.

Findings: From 2008 to 2020, the annual incidence and prevalence rates of specific mutations (Ala97Ser) leading to ATTRv amyloidosis with polyneuropathy were 0.04-1.14 and 0.04-4.79 per million in Taiwan, respectively. In Taiwan, these patients exhibited male predominance with a mean age at validation of 62.75 years. At the 5th year after validation, patients exhibited a survival rate of approximately 50%, with higher mortality in male patients (hazard ratio [HR]: 2.22, 95% confidence interval [CI]: 1.15-4.31) and patients older at validation (HR: 1.10, 95% CI: 1.06-1.15). The two most common departments in outpatient were neurology and family medicine, and neurology and cardiology in inpatient. The three most common causes of death registered were unspecified amyloidosis (30.6%), organ-limited amyloidosis (20.9%), and neuropathic heredofamilial amyloidosis (9.7%).

Interpretation: The annual prevalence rate of specific mutation (Ala97Ser)-dominant ATTRv amyloidosis with polyneuropathy in Taiwan is comparable to the mid- to high-prevalence country level of the research by Schmidt et al. The extraordinarily high mortality, especially among patients older at validation, may reflect the inadequate awareness and the necessity of early intervention with novel disease-modifying regimens.