Glycemia Reduction in Type 2 Diabetes - Glycemic Outcomes

N Engl J Med. 2022 Sep 22;387(12):1063-1074. doi: 10.1056/NEJMoa2200433.


Background: The comparative effectiveness of glucose-lowering medications for use with metformin to maintain target glycated hemoglobin levels in persons with type 2 diabetes is uncertain.

Methods: In this trial involving participants with type 2 diabetes of less than 10 years' duration who were receiving metformin and had glycated hemoglobin levels of 6.8 to 8.5%, we compared the effectiveness of four commonly used glucose-lowering medications. We randomly assigned participants to receive insulin glargine U-100 (hereafter, glargine), the sulfonylurea glimepiride, the glucagon-like peptide-1 receptor agonist liraglutide, or sitagliptin, a dipeptidyl peptidase 4 inhibitor. The primary metabolic outcome was a glycated hemoglobin level, measured quarterly, of 7.0% or higher that was subsequently confirmed, and the secondary metabolic outcome was a confirmed glycated hemoglobin level greater than 7.5%.

Results: A total of 5047 participants (19.8% Black and 18.6% Hispanic or Latinx) who had received metformin for type 2 diabetes were followed for a mean of 5.0 years. The cumulative incidence of a glycated hemoglobin level of 7.0% or higher (the primary metabolic outcome) differed significantly among the four groups (P<0.001 for a global test of differences across groups); the rates with glargine (26.5 per 100 participant-years) and liraglutide (26.1) were similar and lower than those with glimepiride (30.4) and sitagliptin (38.1). The differences among the groups with respect to a glycated hemoglobin level greater than 7.5% (the secondary outcome) paralleled those of the primary outcome. There were no material differences with respect to the primary outcome across prespecified subgroups defined according to sex, age, or race or ethnic group; however, among participants with higher baseline glycated hemoglobin levels there appeared to be an even greater benefit with glargine, liraglutide, and glimepiride than with sitagliptin. Severe hypoglycemia was rare but significantly more frequent with glimepiride (in 2.2% of the participants) than with glargine (1.3%), liraglutide (1.0%), or sitagliptin (0.7%). Participants who received liraglutide reported more frequent gastrointestinal side effects and lost more weight than those in the other treatment groups.

Conclusions: All four medications, when added to metformin, decreased glycated hemoglobin levels. However, glargine and liraglutide were significantly, albeit modestly, more effective in achieving and maintaining target glycated hemoglobin levels. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; GRADE number, NCT01794143.).

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Blood Glucose* / analysis
  • Comparative Effectiveness Research
  • Diabetes Mellitus, Type 2* / blood
  • Diabetes Mellitus, Type 2* / drug therapy
  • Dipeptidyl-Peptidase IV Inhibitors / adverse effects
  • Dipeptidyl-Peptidase IV Inhibitors / therapeutic use
  • Drug Therapy, Combination
  • Glucagon-Like Peptide-1 Receptor / agonists
  • Glucagon-Like Peptide-1 Receptor / therapeutic use
  • Glycated Hemoglobin* / analysis
  • Humans
  • Hypoglycemic Agents* / adverse effects
  • Hypoglycemic Agents* / therapeutic use
  • Insulin Glargine / adverse effects
  • Insulin Glargine / therapeutic use
  • Liraglutide / adverse effects
  • Liraglutide / therapeutic use
  • Metformin / adverse effects
  • Metformin / therapeutic use
  • Sitagliptin Phosphate / adverse effects
  • Sitagliptin Phosphate / therapeutic use
  • Sulfonylurea Compounds / adverse effects
  • Sulfonylurea Compounds / therapeutic use
  • Treatment Outcome


  • Blood Glucose
  • Dipeptidyl-Peptidase IV Inhibitors
  • Glucagon-Like Peptide-1 Receptor
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Sulfonylurea Compounds
  • Insulin Glargine
  • glimepiride
  • Liraglutide
  • Metformin
  • Sitagliptin Phosphate

Associated data