Bruising: A Neglected, Though Patient-Relevant Complication of Insulin Injections Coming to Light from a Real-Life Nationwide Survey

INTRODUCTION: Despite the availability of sophisticated devices and suitable recommendations on how to best perform insulin injections, lipohypertrophy (LH) and bruising (BR) frequently occur as a consequence of improper injection technique. AIM: The purpose of this nationwide survey was to check literature-reported LH risk factors or consequences for any association with BR METHOD: This was a cross-sectional, observational, multicenter study based on the identification of skin lesions at all patient-reported insulin injection sites in 790 subjects with diabetes. General and injection habit-related elements were investigated as possible BR risk factors. RESULTS: While confirming the close relationship existing between LH and a full series of factors including missed injection site rotation, needle reuse, long-standing insulin treatment, frequent hypoglycemic events (hypos), and great glycemic variability (GV), the observed data could find no such association with BR, which anyhow came with high HbA1c levels, missed injection site rotation, and long-standing insulin treatment. CONCLUSION: BR most likely depends on the patient’s habit of pressing the injection pen hard onto the skin. Despite being worrisome and affecting quality of life, BR seems to represent a preliminary stage of LH but does not affect the rate of hypos and GV. TRIAL REGISTRATION: 207/19.09.2017