Rotation of the anatomic regions used for insulin injections and day‐to‐day variability of plasma glucose in Type 1 diabetic subjects

The paper by Bantle and colleagues from the University of Minnesota, Minneapolis, assesses the day-to-day variation in blood glucose concentrations following the commonly employed clinical practice or rotating anatomical sites for insulin injection. Twelve patients with insulin-dependent diabetes had blood glucose profiles measured following insulin injections given in the abdomen for three days and then rotated around the arms, abdomen and thighs for three days using a cross-over protocol. Considerable variation in terms of insulin absorption was found between the different injections sites and there was significantly less variability if insulin injections were confined to the abdomen alone. By following the common clinical practice of rotating sites for insulin injection, considerable day-to-day variation in blood glucose concentration can result from differences in insulin absorption. Therefore, the authors recommend that patients restrict insulin injections to a single site, preferably the abdomen, to reduce this variation and allow greater precision of insulin administration. The second paper by Jonathan Thow and Philip Home reviews the technique of insulin injection and, in particular, the depth of needle insertion. They observe that the change in the angle of insulin injection from 45° to a near perpendicular injection has important considerations in terms of insulin absorption, particularly for the thin patient. In such patients insulin may be injected almost into the muscle layer beneath the subcutaneous tissue, which will lead to variability in insulin absorption, often at a much quicker rate. A greater and more variable effect of physical exercise was also noted with intra muscular injection. Variability of insulin absorption after intra muscular injection also occurs between different types of insulin. Isophane insulins show considerable variability and are best not given via the intra muscular route.