Objective: Sodium glucose co-transporter 2 (SGLT2) inhibitors, like dapagliflozin, have demonstrated favorable effects in patients with type 2 diabetes (T2D). However, there are limited reports in the literature regarding the glucose lowering effects of SGLT2 inhibitors in actual clinical settings. Methods: The post-marketing surveillance data from a longitudinal prospective study of 2,007 T2D patients who were prescribed dapagliflozin (10 mg/day) were analyzed.Results: After 12 weeks of dapagliflozin treatment, glycated hemoglobin (HbA1c) and body mass index were significantly decreased (P < 0.001) from 8.1 ± 1.3% to 7.5 ± 1.2% and from 28.1 ± 4.4 kg/m2 to 27.6 ± 4.2 kg/m², respectively. Both body weight and HbA1c were reduced in 799 patients (67.7%), and HbA1c was lowered in 886 patients (75.1%). Younger age, male sex, shorter diabetes duration, higher baseline HbA1c and estimated glomerular filtration rate (eGFR), and add-on therapy were associated with stronger HbA1c reduction after dapagliflozin use (all P < 0.05). Moreover, subgroup analysis of eGFR of subjects with renal hyperfiltration (eGFR ≥ 120 mL/min/1.73m²) showed the largest reduction in glucose level (% change, -9.5; 95% CI, -6.8 to -12.3 for HbA1c; P < 0.001). Multivariable logistic regression analysis showed that recent T2D diagnosis and higher HbA1c at baseline in patients who received an add-on regimen of dapagliflozin were statistically significantly associated with a dapagliflozin response (all P < 0.05). Conclusion: Dapagliflozin provides a benefit on glycemic control and body weight. Patients in a relatively early stage of the course of diabetes with renal hyperfiltration might be more suitable for and reap maximal benefit from dapagliflozin treatment.