Natural history and outcome in systemic AA amyloidosis

N Engl J Med. 2007 Jun 7;356(23):2361-71. doi: 10.1056/NEJMoa070265.


Background: Deposition of amyloid fibrils derived from circulating acute-phase reactant serum amyloid A protein (SAA) causes systemic AA amyloidosis, a serious complication of many chronic inflammatory disorders. Little is known about the natural history of AA amyloidosis or its response to treatment.

Methods: We evaluated clinical features, organ function, and survival among 374 patients with AA amyloidosis who were followed for a median of 86 months. The SAA concentration was measured serially, and the amyloid burden was estimated with the use of whole-body serum amyloid P component scintigraphy. Therapy for inflammatory diseases was administered to suppress the production of SAA.

Results: Median survival after diagnosis was 133 months; renal dysfunction was the predominant disease manifestation. Mortality, amyloid burden, and renal prognosis all significantly correlated with the SAA concentration during follow-up. The risk of death was 17.7 times as high among patients with SAA concentrations in the highest eighth, or octile, (>or=155 mg per liter) as among those with concentrations in the lowest octile (<4 mg per liter); and the risk of death was four times as high in the next-to-lowest octile (4 to 9 mg per liter). The median SAA concentration during follow-up was 6 mg per liter in patients in whom renal function improved and 28 mg per liter in those in whom it deteriorated (P<0.001). Amyloid deposits regressed in 60% of patients who had a median SAA concentration of less than 10 mg per liter, and survival among these patients was superior to survival among those in whom amyloid deposits did not regress (P=0.04).

Conclusions: The effects of renal dysfunction dominate the course of AA amyloidosis, which is associated with a relatively favorable outcome in patients with SAA concentrations that remain in the low-normal range (<4 mg per liter).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age of Onset
  • Aged
  • Aged, 80 and over
  • Amyloidosis* / blood
  • Amyloidosis* / complications
  • Amyloidosis* / mortality
  • Arthritis / complications
  • Child
  • Disease Progression
  • Familial Mediterranean Fever / complications
  • Female
  • Humans
  • Infections / complications
  • Kaplan-Meier Estimate
  • Kidney Failure, Chronic / etiology
  • Male
  • Middle Aged
  • Risk Factors
  • Serum Amyloid A Protein / metabolism*


  • Serum Amyloid A Protein