Early insulin initiation may benefit older adults with type 2 diabetes and inadequate glycemic control

Older patients with type 2 diabetes and inadequate glycemic control may benefit from earlier initiation of insulin therapy, according to a recent study.

Researchers performed a retrospective cohort study using data from a Medicare Advantage insurance plan to compare outcomes with early versus delayed insulin initiation in Medicare beneficiaries. Patients were classified by how many classes of oral antidiabetes drugs they had taking before insulin was started. Those who had taken 1 class were considered early insulin initiators, and those who had taken 3 or more classes were considered delayed insulin initiators. The primary outcomes at 1 year of follow-up were change in HbA1c, percentage of patients with an HbA1c below 8.0%, hypoglycemic events, and total health care costs. The study results appeared in the May Journal of the American Geriatrics Society.

A total of 14,669 patients were included in the study analysis. The mean age was 74 years; 78% were white, and 49% were women. Overall, 4,028 patients (27.5%) had data available on HbA1c at baseline and at 1 year of follow-up. Thirty-two percent had early insulin initiation, 48% had started insulin after trying 2 classes of oral antidiabetes drugs, and 20% had delayed insulin initiation. At 1 year, the unadjusted reduction in HbA1c was 0.9% ± 3.7% for patients who had taken 1 class of oral antidiabetes drugs, 0.7% ± 2.4% for those who had taken 2, and 0.5% ± 3.6% for those who had taken 3 or more. Patients who initiated insulin early had significantly greater reduction in HbA1c level (adjusted P<0.001) and were more likely to have achieved an HbA1c below 8.0% (adjusted odds ratio, 1.30; 95% CI, 1.18 to 1.43). Total cost and hypoglycemic events during 1-year follow-up did not appear to differ between early and delayed initiators.

The authors acknowledged that their study relied on observational data and could not assess actual medication use or type of basal insulin used. In addition, they could not differentiate between continued and 1-time insulin use, HbA1c values were not available for all patients, and the results may not be generalizable to other populations with type 2 diabetes, among other limitations. However, they concluded that their findings suggest a benefit from early insulin initiation among older Medicare beneficiaries with type 2 diabetes, specifically a clinically significant reduction in HbA1c without higher risk or costs, especially in patients whose glycemic control is inadequate.

“In the absence of clinical trials that include older adults with complex chronic conditions … these findings fill a crucial knowledge gap regarding the association between early insulin initiation and clinical and economic outcomes in older adults with [type 2 diabetes mellitus],” the authors wrote.