Impact of Non-Cardiac Clinicopathologic Characteristics on Survival in Transthyretin Amyloid Polyneuropathy

INTRODUCTION: Hereditary (variant) transthyretin amyloidosis (ATTRv) with polyneuropathy (ATTR-PN) is a rare genetic disorder that causes progressive autonomic and sensorimotor neuropathy, severe disability, and death within 10 years of onset. Previous studies have primarily focused on how baseline cardiac characteristics affect mortality, but the impact of non-cardiac baseline characteristics is less defined. METHODS: We systematically searched PubMed/Medline (1990–2019) to identify studies that assessed the impact of baseline ATTR-PN characteristics on survival. Outcomes were first summarized descriptively. Extracted survival data were then disaggregated, and parametric mixture models were used to assess survival differences among patient groups defined by factors known to affect survival. RESULTS: The search yielded 1193 records, of which 35 were retained for analysis. Median survival ranged from 0.5 to > 25 years. The largest survival differences were between cohorts who underwent liver transplantation (LTx) versus those who did not. Among LTx cohorts, pre-LTx ATTR-PN disease duration ≥ 7 years, poor nutritional status, and late disease onset reduced median survival by 13, 12, and 10 years, respectively. Other prognostic survival factors included non-Val30Met genotype and baseline presence of urinary incontinence, erectile dysfunction, or muscle weakness. CONCLUSION: Survival in patients with ATTR-PN is highly variable and affected by non-cardiac baseline characteristics, such as autonomic dysfunction, large fiber involvement, late-onset disease, and non-Val30Met mutation. Careful interpretation of these findings is warranted given that this synthesis did not control for differences between studies. Survival in patients with ATTR-PN remains poor among those who are untreated or with delayed diagnosis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40120-020-00183-7) contains supplementary material, which is available to authorized users.