Glycemic control after initiating basal insulin therapy in patients with type 2 diabetes: a primary care database analysis

Background: When target glycated hemoglobin (HbA(1c)) levels are not reached, basal insulin therapy should be considered in type 2 diabetes. The objective of this report was to describe the predictors of glycemic control (strict criterion: HbA(1c) <6.5%) during the first year after initiating basal insulin therapy in primary care. Methods: The study applied a retrospective approach using a nationwide database in Germany (Disease Analyzer, IMS Health, January 2008 to December 2011, including 1,024 general and internal medicine practices). Potential predictors of glycemic control considered were age, sex, duration of diabetes, type of basal insulin, comedication with short-acting insulin, baseline HbA(1c), previous oral antidiabetic drugs, diabetologist care, private health insurance, macrovascular and microvascular comorbidity, and concomitant medication. Multivariable logistic regression models were fitted with glycemic control as the dependent variable. Results: A total of 4,062 type 2 diabetes patients started basal insulin (mean age 66 years, males 53%, diabetes duration 4.8 years, mean HbA(1c) 8.8%), of whom 295 (7.2%) achieved an HbA(1c) <6.5% during the one-year follow-up. Factors positively associated with HbA(1c) <6.5% in logistic regression were male sex (odds ratio 1.59, 95% confidence interval 1.23-2.04), insulin glargine (reference neutral protamine Hagedorn; odds ratio 1.43, 95% confidence interval 1.09-1.88), short-acting insulin (odds ratio 1.33, 95% confidence interval 1.01-1.76), and prior treatment with metformin, dipeptidyl peptidase-4 inhibitors, and diuretics. Lipid-lowering drugs were associated with a lower odds of reaching the glycemic target. Conclusion: Few type 2 diabetes patients (7%) reached the glycemic target (HbA(1c) <6.5%) after one year of basal insulin therapy. Achievement of the glycemic target was associated with type of basal insulin, additional short-acting insulins, previous antidiabetic medication, and other comedication, eg, diuretics or lipid-lowering drugs.