No Evidence of Amyloidosis in Type I Diabetics Treated with Continuous Subcutaneous Insulin Infusion

A recent study has demonstrated secondary amyloidosis in dogs treated with continuous intravenous insulin infusion. Since elevated levels of serum amyloid A protein (SAA) and diminished amyloid fibril degrading activity (AFDA) are associated with amyloidosis, we measured SAA and AFDA in ten type I diabetics treated with continuous subcutaneous insulin infusion and in five conventionally treated patients. Only one pump- and one conventionally treated patient had detectable but low SAA levels, comparable with these seen in healthy controls. In patients with secondary amyloidosis the mean SAA level was 24-fold higher than in controls (P < 0.001). Similarly, in both diabetic groups, AFDA was normal whereas it was reduced by 41% in patients with amyloidosis (P < 0.001). Furthermore, no local amyloidosis was seen at the infusion site in any of the patients studied. Thus, our data fail to provide any evidence of secondary amyloidosis in patients treated for 3–40 mo with continuous subcutaneous insulin infusion.