Incidence and survival in non-hereditary amyloidosis in Sweden

Kari Hemminki,Asta Försti,Xinjun Li,Kristina Sundquist,Jan Sundquist

doi:10.1186/1471-2458-12-974

Abstract

BackgroundAmyloidosis is a heterogeneous disease caused by deposition of amyloid fibrils in organs and thereby interfering with physiological functions. Hardly any incidence data are available and most survival data are limited to specialist clinics.MethodsAmyloidosis patients were identified from the Swedish Hospital Discharge and Outpatients Registers from years 2001 through 2008.ResultsThe incidence of non-hereditary amyloidosis in 949 patients was 8.29 per million person-years and the diagnostic age with the highest incidence was over 65 years. Secondary systemic amyloidosis showed an incidence of 1 per million and a female excess and the largest number of subsequent rheumatoid arthritis deaths; the median survival was 4 years. However, as rheumatoid arthritis deaths also occurred in other diagnostic subtypes, the incidence of secondary systemic amyloidosis was likely to be about 2.0 per million. The median survival of patients with organ-limited amyloidosis was 6 years. Most myeloma deaths occurred in patients diagnosed with unspecified or ‘other’ amyloidosis. These subtypes probably accounted for most of immunoglobulin light chain (AL) amyloidosis cases; the median survival time was 3 years.ConclusionsThe present diagnostic categorization cannot single out AL amyloidosis in the Swedish discharge data but, by extrapolation from myeloma cases, an incidence of 3.2 per million could be ascribed to AL amyloidosis. Similarly, based on rheumatoid arthritis death rates, an incidence of 2.0 could be ascribed to secondary systemic amyloidosis.

Highlights

Amyloidosis is a heterogeneous disease caused by deposition of amyloid fibrils in organs and thereby interfering with physiological functions
The abbreviations for the amyloids are constructed by starting with an ‘A’ for amyloid and adding a suffix designating the precursor protein, e.g., AL is amyloid derived from immunoglobulin light chain precursor
According to causes of death in rheumatoid arthritis patients, 5.8% have been ascribed to amyloidosis but the proportion appears to be declining with time due to a better control of the inflammation [6,10,11]

Summary

Introduction

Amyloidosis is a heterogeneous disease caused by deposition of amyloid fibrils in organs and thereby interfering with physiological functions. Amyloidosis is a heterogeneous group of diseases characterized by fibrillar protein deposits, amyloids, localized in a single organ or systematically in many organs [1,2,3]. Other systemic forms include reactive (AA with serum amyloid A as the precursor) and senile (SSA, transthyretin) amyloidosis [4]. AA amyloidosis is a secondary condition in response to chronic inflammation or even cancer; e.g., some 20% of rheumatoid arthritis patients show some amyloid accumulation in the course of their disease [7]. The most common and wide-spread hereditary amyloidosis, familial amyloid polyneuropathy (FAP), is caused by transthyretin mutations [12,13]. Hereditary amyloidosis is outside the scope of the present study, and will only be referred to in the context of diagnostic specificity for non-hereditary amyloidosis

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