OBJECTIVES: Healthcare Effectiveness Data and Information Set (HEDIS) measures are used to rate health plan performance; HEDIS quality of diabetes care measures include glycated hemoglobin (HbA1c) categories <7% or <8%, which define good control, and >9%, which defines poor control. Dapagliflozin, a sodium glucose cotransporter 2 inhibitor, is under clinical development for the treatment of type 2 diabetes mellitus (T2DM). We assessed the effect of dapagliflozin on achieving HbA1c outcomes by HEDIS categories. METHODS: Pooled data for dapagliflozin 10 mg/day (N=1066) vs placebo (N=1257) from nine 24-week, phase 3, randomized, placebo-controlled trials in patients with T2DM, including monotherapy (NCT00528372, NCT00736879) and add-on to metformin (NCT00528879, NCT00855166), glimepiride (NCT00680745), pioglitazone (NCT00683878), or insulin (NCT00673231), or initial combination with metformin (NCT00859898, NCT00643851) trials, were analyzed. Adjusted mean change in HbA1c from baseline to week 24 with dapagliflozin vs placebo was determined for patients with baseline HbA1c of <8%, ≥8% to<9%, and ≥9%. Additionally, the proportions of patients achieving HEDIS HbA1c categories of <7%, <8%, and >9% were assessed. RESULTS: Placebo-subtracted adjusted mean changes in HbA1c (95% CI) at 24 weeks with dapagliflozin were –0.45% (–0.56%, –0.33%), –0.62% (–0.75%, –0.48%), and –0.78% (–0.93%, –0.63%) for patients with baseline HbA1c <8%, ≥8% to<9%, and ≥9%, respectively. Compared with placebo, more patients achieved HbA1c <7% (39.4% vs 24.4%) and <8% (79.5% vs 60.6%) and fewer patients remained at or worsened to HbA1c >9% (4.2% vs 13.9%) with dapagliflozin. CONCLUSIONS: Dapagliflozin 10 mg/day reduced HbA1c across all baseline HbA1c categories; greater reductions were seen in patients with higher baseline HbA1c. Substantially more patients attained HEDIS HbA1c categories of <7% and <8% and substantially fewer patients remained at or worsened to HbA1c >9% with dapagliflozin, compared with placebo. Collectively, dapagliflozin provided better glycemic control than placebo over a range of HbA1c levels.