Delayed insulin absorption due to subcutaneous edema

A prospective study to determine if subcutaneous edema interferes with insulin absorption was performed. Forty-six patients entered the study. Three groups were formed. Twenty patients with generalized edema (Group 1), ten of them with non-insulin dependent diabetes mellitus (NIDDM). Twenty patients without edema (Group II). 10 of them with NIDDM; and six patients with mild edema (Group III). The disappearance of I125-insulin was measured throughout 360 minutes. The rate of absorption in group I was significantly lower and delayed than in group II. The amount of insulin absorbed at 360 minutes was 3 to 4 fold lower in group I than in group II (p 0.001). Group III had intermediate values. The peak of plasma I125-insulin level was 3 to 4 fold lower in group I than group II. The impairment of insulin absorption in subjects with edema was more evident in those with NIDDM. In conclusion, this study demonstrates that subcutaneous edema impairs insulin absorption. Insulin absorption from subcutaneous tissue varies due to several conditions, resulting in a difficult glycemic control. Previous studies have shown that insulin absorption is affected by several factors as the site of injection, room and skin temperature, physical exercise, the thickness of adipose tissue, local massage, and local degradation of insulin. Edema due to chronic complications such as nephropathy and cardiopathy often occurs in long-standing diabetic subjects. However, the effects of edema of the skin and subcutaneous tissue on insulin absorption has not been previously examined. The aim of this study was to assess if edema affects the absorption of insulin.