Long-term efficacy of triple oral therapy for type 2 diabetes mellitus

Endocr Pract. Jul-Aug 2002;8(4):271-5. doi: 10.4158/EP.8.4.271.


Objective: To report the status of 35 patients with type 2 diabetes mellitus approximately 3 years after the initiation of triple oral antidiabetic therapy--with a sulfonylurea, metformin, and a thiazolidinedione.

Methods: Study patients were assessed for the need for the addition of insulin, and follow-up clinical and laboratory findings were analyzed.

Results: At a mean follow-up of 37 months (range, 18 to 45), 26 (74%) of 35 patients (group A) had well-controlled blood glucose levels on triple oral therapy, with a mean glycated hemoglobin (HbA1c) value of 6.9 +/- 0.3% (upper limit of normal, 6.5%). In the nine other patients (group B), triple oral therapy failed and the use of insulin was necessary after a mean duration of 30 months (range, 18 to 42); the mean HbA1c in these patients was 8.8 +/- 0.5%. Both group A and B gained similar amounts of weight during the study period (14.2 +/- 2.1 lb versus 11.6 +/- 3.8 lb, respectively; P = 0.54). A search for potential predictors of success or failure revealed that both groups had similar baseline characteristics, including age, duration of diabetes, weight, body mass index, HbA1c, and baseline stimulated C-peptide levels, and none of these factors demonstrated a significant correlation with the response to therapy. The only difference found between the two groups was a significant increase in the stimulated C-peptide levels (from 3.6 +/- 0.9 ng/mL to 5.2 +/- 1.1 ng/mL; P = 0.002) during follow-up in the group that had good glycemic control with triple oral therapy, in comparison with a nonsignificant increase (from 3.7 +/- 0.8 ng/mL to 4.2 +/- 0.4 ng/mL; P = 0.46) in the group that failed to maintain glycemic control on triple oral therapy.

Conclusion: Triple oral antidiabetic therapy is an effective long-term treatment for a substantial proportion of patients with type 2 diabetes who initially achieve glycemic control with triple oral therapy, particularly those in whom production of endogenous insulin is increased when a thiazolidinedione is added.

MeSH terms

  • Adolescent
  • Adult
  • Body Mass Index
  • C-Peptide / blood
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Drug Therapy, Combination
  • Glycated Hemoglobin A / analysis
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Insulin / therapeutic use
  • Metformin / therapeutic use*
  • Middle Aged
  • Sulfonylurea Compounds / therapeutic use*
  • Thiazoles / therapeutic use*
  • Thiazolidinediones*
  • Time Factors
  • Weight Gain


  • C-Peptide
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Insulin
  • Sulfonylurea Compounds
  • Thiazoles
  • Thiazolidinediones
  • Metformin
  • 2,4-thiazolidinedione