Glycemic control among patients with type 2 diabetes who initiate basal insulin: a retrospective cohort study.

OBJECTIVE

To examine changes in glycemic control for patients with type 2 diabetes mellitus (T2DM) after initiation of basal insulin and factors associated with improved glycemic control.

METHODS

An analysis of retrospective medical records of patients with T2DM was examined using Humedica's electronic medical records database (January 2007-August 2012). Patients with T2DM, initiating basal insulin, age ≥ 21 years, with a recorded HbA1c test in both the 1 year prior and the 2 years post-initiation were included. A multivariate regression examined factors associated with changes in glycemic control. Logistic regressions examined factors associated with improvements or worsening of glycemic control, compared to relatively unchanged glycemic control.

RESULTS

Many (14,457) individuals met the inclusion-exclusion criteria. Multivariate analyses revealed that older age (p < 0.0001), residence in the Western region of the US (vs South) (p < 0.0001), Medicare insurance vs Medicaid or being uninsured (p = 0.0138), and higher household income (p = 0.0065) were associated with improved glycemic control. Patients diagnosed with comorbid peripheral vascular disease (p = 0.0072), cancer (p = 0.0019), obesity (p = 0.0002), moderate (p = 0.0103), and severe chronic kidney disease (p < 0.0001), or end-stage renal disease (p = 0.0075) in the pre-period were found to have significantly improved glycemic control in the post-period. Use of prandial insulin (p = 0.0087), pre-mix insulin (p = 0.0003) in the pre-period, a higher pre-period HbA1c score (p < 0.0001), and longer duration between pre-period and post-period HbA1c testing (p < 0.0001) were significantly associated with higher HbA1c levels in the post-period.

LIMITATIONS

Analyses rely on electronic medical records which cannot capture patient healthcare utilization occurring outside of the data capture system. Analyses do not control for insulin dosage or type of basal insulin prescribed.

CONCLUSIONS

Among patients with T2DM treated with basal insulin, a number of factors may influence glycemic outcomes. These findings suggest a role for a more personalized approach to the treatment of patients with T2DM.