Amyloid load in fat tissue reflects disease severity and predicts survival in amyloidosis

• Published in: Arthritis care & research (2010) Vol. 62; no. 3; pp. 296 - 301
• Main Authors: van Gameren, Ingrid I., Hazenberg, Bouke P. C., Bijzet, Johan, Haagsma, Elizabeth B., Vellenga, Edo, Posthumus, Marcel D., Jager, Pieter L., van Rijswijk, Martin H.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-03-2010
• Subjects: Abdominal Fat - chemistry; Adolescent; Adult; Aged; Aged, 80 and over; Amyloidosis - diagnosis; Female; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Prognosis; Prospective Studies; Serum Amyloid P-Component - analysis; Severity of Illness Index; Young Adult
• ISSN: 2151-464X; 2151-4658
• DOI: 10.1002/acr.20101

Objective
The severity of systemic amyloidosis is thought to be related to the extent of amyloid deposition. We studied whether amyloid load in fat tissue reflects disease severity and predicts survival.
Methods
We studied all consecutive patients with systemic amyloidosis seen between January 1994 and January 2007 in our tertiary referral center. Congo red–stained abdominal fat smears were graded by 2 observers using a validated semiquantitative scoring system. Disease severity was measured by the total number of major organs involved and the extravascular retention of the serum amyloid P component (EVR24). The association of amyloid load in fat tissue with disease severity and overall survival was studied using multiple regression analysis.
Results
Two hundred twenty patients were included in the study (120 with AL amyloidosis, 66 with AA amyloidosis, and 34 with ATTR amyloidosis). Amyloid grade in fat tissue was associated with the number of major organs involved and EVR24. Female sex turned out to be associated with a higher grade of amyloid in fat tissue than male sex. Amyloid grade in fat tissue was an independent predictor of decreased survival, as were heart involvement, the number of organs involved, AA or AL type of amyloid, and age.
Conclusion
The amount of amyloid in subcutaneous fat tissue in systemic amyloidosis reflects disease severity, as measured by the number of organs involved and EVR24, and predicts decreased survival independent of other well‐known factors.