Endocrine Abstracts

Background: The absorption kinetics of soluble insulin are complex. Soluble insulin is absorbed after a delay as the hexameric form dissociates before being absorbed as the dimer.Patients using soluble insulin are instructed to inject 15-30 minutes before meals.In practice few patients comply with these recommendations.The aims of this study were to identify the proportion of patients injecting at the recommended time and to assess any association between injection timing and glycaemic control.
Methods: 50 patients were assessed over 4 weeks. An 8-part questionnaire determined type and duration of diabetes, timing of injection and reasons for this.
Results: 50 % of patients were male; average age 59 years (range 27-88); 32% had Type 1 diabetes, 64% had Type 2 diabetes; average duration of diabetes 19 years (range3-40).44% injected insulin less than 15 minutes before meals. Of these, 45% were aware of the correct time of injection. 25 per cent were unaware of the correct time.All patients injecting 15-30 minutes before meals did so because medical staff had instructed them on this. Patients injecting at sub-optimal times did so for convenience; 8 patients (16% of the study sample) recalled being told to inject at theses times by medical staff. Diabetic Nurse Specialists were the main source of information for patients. There was no correlation between injection timing and HbA1c, sex or age of patient.
Conclusion: Patient compliance with soluble insulin is poor in relation to timing of injection before meals. This is due to a combination of perceived inconvenience and lack of awareness of the correct time of injection. 0pportunities exist to re-educate patients about this. There was no correlation between injection times and HbA1c levels. The overall importance of insulin injection timing in relation to other proven factors in diabetic control therefore remains unclear.