Spotlight on type 1 diabetes in older adults

One recent study in older patients with type 1 diabetes found an association between a recent history of severe hypoglycemia and impaired cognition, while another suggested that continuous subcutaneous insulin infusions are safe and effective in this population.

Two studies in the past month looked at optimizing treatment in older adults with type 1 diabetes.

The first study used data from the Study of Longevity in Diabetes (SOLID) to examine the association between severe hypoglycemia and cognitive function in adults with type 1 diabetes. Participants self-reported recent severe hypoglycemia, defined as an episode of low blood glucose levels that led to an inpatient stay or ED visit within the past 12 months, as well as their lifetime history of such episodes. Patients' global and domain-specific cognition, including language, executive function, episodic memory, and simple attention, were assessed, and associations between severe hypoglycemia and impaired cognition were evaluated. The study results were published Dec. 27, 2019, by Diabetes Care.

The study included 718 adults with type 1 diabetes. Participants' mean age was 67.2 years, 50.70% were women, and 85.65% were white. Average duration of diabetes was 39 years, with 28 years as the average age of onset. Overall, 32% of patients reported recent episodes of severe hypoglycemia, and 50% reported severe hypoglycemia over their lifetime. Patients with a recent history of severe hypoglycemia had significantly lower global cognition scores than those without. In domain-specific analyses, patients with a recent history of severe hypoglycemia also had lower scores on language, executive function, and episodic memory, while those with severe hypoglycemia over their lifetime had significantly lower executive function. An association was seen between recent severe hypoglycemia and both impaired global cognition and cognitive impairment in the language domain (odds ratios, 3.22 [95% CI, 1.30 to 7.94] and 3.15 [95% CI, 1.19 to 8.29], respectively).

Limitations of the study include its reliance on self-reported data, lack of data on patients' long-term glycemic control, and potential lack of generalizability, the authors noted. However, they concluded that severe hypoglycemia is strongly associated with impaired cognition in older adults with type 1 diabetes and said that this is, to their knowledge, the first large-scale study to address this question in this population. “Our findings underscore the importance of continued vigilance and management to prevent SH [severe hypoglycemia] in this older population, as the aging brain may be particularly susceptible to SH-related cognitive decline,” they wrote.

In the next study, a retrospective analysis, researchers used data from a registry in Austria, Germany, and Switzerland to determine the percentage of adults with type 1 diabetes who were 60 years of age or older and using continuous subcutaneous insulin infusion versus insulin injection therapy. They also compared clinical characteristics and outcomes for each type of therapy. The study results were published online Dec. 18, 2019, by Diabetic Medicine.

A total of 9,547 patients were included in the analysis, 1,404 who used continuous subcutaneous insulin infusion and 8,143 who used insulin injection therapy. Data obtained from the registry in March 2019 represented patients' most recent year of treatment. Use of continuous subcutaneous insulin infusion increased overall, from 12% in 2008 to 23% in 2018. Among patients ages 60 years to 70 years, 70 years to younger than 80 years, and 80 years and older, increases from 2008 to 2018 were 16% to 31%, 9% to 18%, and 2% to 7%, respectively. Mean duration of continuous subcutaneous insulin use was six years.

In comparisons adjusted for age, sex, and diabetes duration, continuous subcutaneous insulin infusion was associated with lower HbA1c levels (7.7% vs. 7.9%), a lower daily insulin dose (0.49 IU/kg vs. 0.61 IU/kg), fewer days spent in the hospital (8.1 days/person-year vs. 11.2 days/person-year), fewer severe hypoglycemic events (0.16 event/person-year vs. 0.21 event/person-year), and fewer episodes of diabetic ketoacidosis (0.06 event/person-year vs. 0.08 event/person-year) when compared with insulin injection.

The authors noted that their results may not be generalizable to other populations and that they could not tell which patients were new versus experienced users of continuous subcutaneous insulin infusion, among other limitations. They concluded that use of continuous subcutaneous insulin infusion is generally safe and effective in older adults with type 1 diabetes and that its use in this population is increasing. However, they noted that while older age shouldn't be a sole exclusion factor, patients' diabetes self-management skills and potential impairments must be considered during shared decision making about treatment.

“More extensive research in different settings on effectiveness, safety and person-reported outcomes (such as well-being) regarding CSII [continuous subcutaneous insulin infusion] in older adults with type 1 diabetes and evidence-based guidelines are needed to help identify those who would most likely benefit from CSII,” the authors concluded.