Compared with injecting insulin from a vial using a syringe, using an insulin pen was linked to better blood glucose control in older adults with type 2 diabetes in a recent study published in the journal Diabetology & Metabolic Syndrome.
As the study authors noted, insulin pens were developed to be a practical option for injecting insulin in people with diabetes who require this drug — including a substantial number of older adults with type 2 diabetes. But there hasn’t been much research on how much this convenience translates into tangible health benefits in this population, such as better blood glucose control. For this study, the researchers recruited 121 older participants with type 2, with an average age of about 66 years old. They were randomly assigned to one of two groups — 61 were assigned to use insulin pens for their injections, and 60 were assigned to use vials and syringes. At the beginning of the study, all participants had an A1C level (a measure of long-term blood glucose control) greater than 8.5%, indicating that their blood glucose was not adequately controlled. Participants in both groups received NPH insulin, which is considered to be intermediate-acting. They also took regular insulin if needed, which is considered to be short-acting and is typically taken around mealtimes.
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Larger A1C reductions in group using insulin pens
At the beginning of the study, the average A1C level in the insulin pen group was 10.34%, while in the syringe group it was 9.90%. After 24 weeks of insulin therapy, the average A1C level dropped to 8.39% in the pen group and 8.85% in the syringe group — indicating a greater drop in the pen group. There were no significant differences between the two groups in adherence to their insulin regimen, frequency or severity of hypoglycemia (low blood glucose), increased or decreased need for insulin or oral medications over time, or progression to needing short-acting insulin to address glucose spikes after meals. There were also no reported differences between the two groups in how diabetes affected their quality of life.
As noted in an article on the study at Endocrinology Advisor, while overall adherence to their designated insulin regimen ended up about the same in the two study groups, there were some differences in how long it took participants to get there. While members of the pen group reached an “adequate adherence average” — taking over 80% of insulin doses as prescribed — after an average of three doctor visits, it took members of the syringe group an average of five doctor visits to reach this level of adherence. This slower start could help explain why A1C didn’t drop as much in the syringe group.
Another potential explanation for the bigger A1C drop in the pen group, though, is simply that this group started out with a higher average A1C level — which might just naturally translate into a bigger drop when similar measures are taken to control blood glucose levels using the same type or types of insulin. More studies are needed to gain a better understanding of how using a syringe or an insulin pen affects blood glucose control in different groups of people with diabetes.