This systematic review was conducted to assess the extent and consequences of missed and mistimed insulin doses in people with diabetes. A total of 30 studies involving 58 617 people with diabetes were included.
Between 12% and 56% of participants with type 1 diabetes had missed one or more insulin dose in the previous month, while 16–23% of people with type 2 diabetes had. Among the latter group, those who were on a basal–bolus regimen were more likely to miss insulin doses compared with those on premixed or basal insulin regimens.
Missed insulin doses were consistently reported to be associated with higher HbA1c, whilst in one study of people with type 2 diabetes, missing around 3–4 basal insulin doses per month resulted in significantly worse glycaemic control. Missed insulin doses were associated with lower health-related quality of life in adolescents with type 1 diabetes and in adults with type 2 diabetes.
Regarding mistimed insulin doses, around 25–30% of people with diabetes (type 1 or type 2) administered their bolus insulin during or after meals, contrary to guidelines, while around 20–26% had mistimed their basal doses in the previous 30 days. Hypoglycaemia was more common in people who took their bolus insulin after meals compared with before or during, and glycaemic control was better in those who took their bolus doses regularly and before meals.
Reasons for missing or mistiming insulin included forgetfulness, disruption to routines (including travelling), obstruction of usual daily activities, fear of hypoglycaemia, stress (including diabetes distress and burnout), injection pain, and embarrassment in public or social situations. Regimen complexity and the challenges of taking insulin at the same time each day were also cited as reasons.
The authors conclude that some individuals continue to struggle with the complexities of diabetes management and the specific challenges of insulin therapy. Approaches that facilitate better diabetes management are needed.
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