Early hypoglycaemia and adherence after basal insulin initiation in a nationally representative sample of Medicare beneficiaries with type 2 diabetes

Aims: To estimate risk factors associated with early hypoglycaemia and its impact on adherence to and persistence with therapy in Medicare Part D beneficiaries with type 2 diabetes who are initiating basal insulin (BI).

Materials and methods: This retrospective analysis used a 5% sample of Medicare files from 2007-2013, identifying beneficiaries with type 2 diabetes initiating BI from 1 January 2008 to 31 December 2012. Early hypoglycaemia was defined as ≥1 hypoglycaemic event ≤6 months postindex. Outcomes included medication adherence and persistence over 12- and 36-month follow-up. Multivariable logistic and Cox regression analyses were conducted to examine factors associated with early hypoglycaemia and BI adherence/persistence.

Results: Of the 14 466 included patients, 1315 (9.1%) experienced hypoglycaemia ≤6 months after initiating BI. Factors associated with early hypoglycaemia were female sex (odds ratio [OR] 1.16 [95% confidence interval [CI] 1.02-1.32]), receipt of a low-income subsidy under Medicare Part D (OR 1.20 [95% CI 1.01-1.43]), high diabetes complication score index (OR 1.08 [95% CI 1.01-1.15]), and hypoglycaemia during the baseline period (OR 4.24 [95% CI 3.63-4.96]). At 12 months, patients with baseline hypoglycaemia were less likely to be adherent to (OR 0.81 [95% CI 0.70-0.93]) and more likely to discontinue (OR 1.33 [95% CI 1.07-1.66]) their insulin therapy. Results were similar at 36 months.

Conclusions: Within 6 months of BI initiation, almost 1 in 10 Medicare Part D beneficiaries experienced hypoglycaemia. Early hypoglycaemia was associated with decreased adherence to BI treatment over 12- and 36-month follow-up.