Background: It was the aim of this study to assess baseline predictors for glycosylated hemoglobin (HbA1c) reduction, treatment-to-target, and insulin glargine dose in patients with an HbA1c level of ≥ 7.5% (58 mmol/mol) at baseline despite 3 months of maximum tolerated dose of metformin under daily conditions.
Subjects and methods: This was an open, multicenter, prospective observational study with a 6-month follow-up including 1,438 patients with type 2 diabetes. Baseline variables independently associated with HbA1c (overall reduction and achievement of target values) and insulin glargine dose used were determined using a stepwise multivariate linear regression analysis.
Results: In a multivariate linear regression analysis (R(2)=0.545) baseline HbA1c (β=-0.722; P<0.001) and retinopathy (β=-0.064; P=0.007) were associated with a greater HbA1c reduction at 6 months, whereas duration of diabetes was associated with a lesser HbA1c reduction (β=0.084; P<0.001). In another multivariate linear regression analysis, weight (odds ratio [OR] 0.99; 95% confidence interval [CI] 0.98 to <1.00), duration of diabetes (OR 0.96; 95% CI 0.93-0.99), and baseline HbA1c (OR 0.65; 95% CI 0.56-0.76) were associated with a reduced likelihood of achieving an HbA1c level of <7% (53 mmol/mol); baseline HbA1c (OR 0.66; 95% CI 0.51-0.85) was the only variable associated with a reduced likelihood of achieving an HbA1c level of <6.5% (48 mmol/mol). In a further analysis (R(2)=0.135) the insulin dose needed was increased in those with a higher body weight (β=0.230; P<0.001), a longer duration of diabetes (β=0.134; P<0.001), a higher baseline HbA1c level (β=0.205; P<0.001), and the presence of microalbuminuria (β=0.096; P=0.003).
Conclusions: Identified predictors of greater HbA1c reduction, target goal achievement, and insulin dose needed may help to optimize the balance of benefits and risks with the use of insulin glargine.