Type 1 Diabetes and the Relationship Between Insulin Regimens and hb A1c
The medical key to management of type 1 diabetes is insulin (along with appropriate nutrition, exercise, etc.). The Diabetes Control and Complications Trial (DCCT) published in 1993 demonstrated that intensive insulin therapy (greater than or equal to 3 injections/day), as compared to conventional insulin therapy (2 shots/day), improved glycemic control and complications were logarithmically related to hb A1c. The greater the hb A1c, the greater the risk of complications increasing by 100 fold (similar to the Richter scale for earthquakes) per 1 hb A1c percentage point. However, controversy still exists in the use of different insulin regimens for glycemic control. It is clear that intensive insulin therapy will improve glycemic control; but what is less clear are the barriers that might play a role in choice of insulin regimens and whether intensive insulin regimens used in pediatrics produce differing A1c results.
Pihoker, Badaru, Anderson, et.al (for the Search for Diabetes in Youth Study), published “Insulin Regimens and Clinical Outcomes in a Type 1 Diabetes Cohort” in Diabetes Care ahead of print: DOI: 10.2337/dc12-0720 in September 2012. The objective of the study was to “examine the patterns and associations of insulin regimens and change in regimens with clinical outcomes in a diverse population of children with recently diagnosed type 1 diabetes.”
The study subjects included 1,606 patients with 36-month follow-up. Insulin regimens and changes in regimens as compared to the initial visit were categorized as follows:
- Basal bolus with insulin pump therapy (most intensive)
- Basal bolus with Glargine/Detemir plus rapid acting analogs
- Multiple daily injections (greater than or equal to 3 injections/day) with Glargine or detemir plus NPH insulin plus regular or rapid acting insulins
- MDI (greater than or equal to 3 injections/day) with any insulin types excluding basal insulin (glargine/detemir)
- One or two injections per day, excluding basal insulin (glargine/detemir)
What were the results?
- 51.7 percent changed to a more intensive regimen; 44.7 percent had no change; 3.6 percent changed to a less intensive regimen.
2. Participants who were younger, non-Hispanic white, and from families with higher income and parental education who had private health insurance were more likely to be in the more intensive or no change groups.
- Younger age, insulin pump therapy, and change to a more intensive insulin
therapy were associated with a greater likelihood of achieving age-related
target A1c levels.
- 86-91 percent of participants checked blood sugars at least 4 times/day. Most importantly, this trend continued after adjustment for baseline age, duration ofdiabetes, sex, household income, parental education, and type of health insurance.
- In almost all comparison visits, the mean level of A1c was significantly lower
when blood glucose monitoring was conducted 4 times/day unadjusted or adjusted for demographic factors. Even more importantly, checking blood sugars greater than or equal to 4 times/day was associated with lower hb A1c within all insulin regimens.
- After 36 months, nearly 75 percent of participants utilized basal-bolus therapy with either MDI or insulin pump therapy.
- Participants on more intensive insulin therapy regimens had lower hb A1c levels over time.
- After adjusting for age and race/ethnicity, the difference in hb A1c between groups was less significant. However, the group with less intensive insulin regimen still had persistently higher hb A1c’s than the multiple injection or groups that did not change their regimens.
What is the take-home message of this study?
According to the authors, these data support “an approach to diabetes management that includes an intensification of insulin regimens over time.” The fact that the more intensive and no change in therapy groups were not significantly different reflects the high frequency of beginning intensive therapies at diagnosis such as starting basal bolus therapy in the “no change” group. However, what still remains to be studied, of course, is to identify the barriers to care in adolescents who do not achieve ideal glycemic outcomes. In addition, according to the authors, as well as in our own practice, there remain significant “socio-demographic” barriers in regard to insulin therapy intensification that will require the work of all members of the diabetes care multidisciplinary team to unravel.