Improvements in glycemic control in type 2 diabetes patients switched from sulfonylurea coadministered with metformin to glyburide-metformin tablets

• Published in: Journal of managed care pharmacy 2003-05, Vol.9 (3), p.256-262
• Main Authors: Duckworth, William, Marcelli, Marco, Padden, Maureen, Kellick, Kenneth, Duhancik, Teresa, Wilhardt, Michelle, Colgan, Kevin, Romie, Alice
• Format: Article
• Language: English
• Subjects: Administration, Oral; Adult; Aged; Blood Glucose - drug effects; Comorbidity; Diabetes Mellitus, Type 2 - drug therapy; Diabetes Mellitus, Type 2 - epidemiology; Drug Combinations; Drug Therapy, Combination; Female; Glipizide - administration & dosage; Glipizide - therapeutic use; Glyburide - administration & dosage; Glyburide - therapeutic use; Glycated Hemoglobin A - analysis; Humans; Hypoglycemic Agents - administration & dosage; Hypoglycemic Agents - therapeutic use; Male; Metformin - administration & dosage; Metformin - therapeutic use; Middle Aged; Obesity - epidemiology; Prospective Studies; Retrospective Studies
• ISSN: 1083-4087; 1944-706X
• DOI: 10.18553/jmcp.2003.9.3.256

To evaluate the change in hemoglobin A1C (A1C) in patients with type 2 diabetes switched from coadministration of a sulfonylurea (SU), glyburide or glipizide, and metformin (SU+Met) to a single glyburide-metformin tablet. A retrospective cohort study design of patients with type 2 diabetes treated at 3 Veterans Affairs Medical Centers and 1 Department of Defense Medical Center was utilized. One hundred percent of patients receiving glyburide-metformin tablets were screened for inclusion. Patients with at least 6 months of prior SU+Met combination therapy and a baseline A1C measured within 35 days prior to or 3 days after switch to glyburide-metformin tablets were included. At least one documented follow-up A1C at >or=90 days after the switch to glyburide-metformin was required for inclusion. Glycemic control, complications, lipid parameters, concomitant medications, and weight were analyzed prior to and following the switch to glyburide-metformin. Seventy-two patient records were included after the disqualification criteria excluded 488 prospective patients. The mean age of the 72 patients was 62 years; average body mass index was 32.9 kg/m2, average baseline A1C was 8.3%, and the average time since diagnosis was 7.6 years. The mean reduction in A1C was 0.6% (P=0.002) at a mean follow-up of 196 days after the switch to glyburide-metformin tablets. Improvement in glycemic control was predominantly seen in patients with a baseline A1C >or=8% in whom a 1.3% mean reduction in A1C (P=0.0002) was achieved despite a lower mean final dose of glyburide. The results of this study suggest that in type 2 diabetic patients with an A1C >or=8%, switching from coadministration of a sulfonylurea plus metformin to combination glyburide-metformin tablets may provide an improvement in glycemic control in the range of a 1.2 to 1.4 absolute percentage point decrease in A1C. A randomized, prospective trial comparing these 2 methods of treatment is needed, however, to determine the precise effect provided by the unique formulation of glyburide in the glyburide-metformin tablet.