Persistence with rapid-acting insulin and its association with A1C level and severe hypoglycemia among elderly patients with type 2 diabetes.

OBJECTIVE: To examine the persistence with rapid-acting insulin (RAI) and its association with clinical outcomes among elderly patients with type 2 diabetes (T2D).

METHODS: This observational, retrospective cohort study analyzed RAI persistence and its association with change in glycated hemoglobin A1c and risk of severe hypoglycemia among elderly (≥65 years) Medicare beneficiaries with T2D who added RAI to their basal insulin regimen.

RESULTS: Among T2D patients with >1 RAI prescriptions (n = 3927), only 21% were persistent. Baseline factors positively associated with RAI persistence (adjusted odds ratio [95% CI]) were: age ≥75 vs. 65-74 years: 1.20 (1.01-1.43); use of ≥3 oral antidiabetes drugs: 1.63 (1.16-2.28); cognitive impairment: 1.34 (1.03-1.73); and A1C >9.0%: 1.58 (1.15-2.17). Elderly T2D patients having emergency department visits (0.73 [0.59-0.91]) and higher RAI out-of-pocket costs (≥$75 vs. $0 - <$6.40: 0.56 [0.44-0.70]) were less likely to be persistent. Persistent RAI users had a significantly higher reduction in A1C (beta coefficient [standard error]): -0.24 (0.10) and lower odds of severe hypoglycemia (adjusted odds ratio [95% CI]): 0.73 (0.53-0.99).

CONCLUSION: Among elderly T2D patients, persistence with RAI added to basal insulin was associated with improved glycemic control and lower risk of severe hypoglycemia. Despite treatment effectiveness, RAI persistence was poor and might be improved by reducing RAI out-of-pocket costs.