Evaluation of glipizide and glyburide in a health maintenance organization.

OBJECTIVE

To determine if there was a difference in the long-term glycemic control, average daily dose, and cost of therapy in patients with noninsulin-dependent diabetes mellitus (NIDDM) treated with glyburide and glipizide in a health maintenance organization (HMO).

DESIGN

Retrospective evaluation of medical and pharmacy records.

SETTING

Multispecialty group practice HMO.

PATIENTS

140 NIDDM patients being treated with either glyburide (n = 70) or glipizide (n = 70) were randomly selected from the populations of patients receiving either drug using computerized pharmacy records.

MAIN OUTCOME MEASURE

Mean daily doses and blood glucose measurements (fasting blood glucose, random blood glucose, hemoglobin A1C) were stratified in 3-month periods from the time the drug therapy was started or the patient first presented to the clinic for a total of 18 months. Long-term glycemic control was defined as fasting blood glucose less than 8.33 mmol/L (150 mg/dL).

RESULTS

The groups were comparable with regard to age (53.4 y glyburide, 56.7 y glipizide), gender (43 M:27 F glyburide, 47 M:23 F glipizide), race (38 W/16 B/16 H glyburide, 45 W/16 B/9 H glipizide), concurrent medical conditions, adverse effects, and compliance. Long-term glycemic control was similar in both groups. Although the number of subjects who were controlled (by definition) tended to be greater in the glyburide group, no clinical or statistical difference was found. There was no statistical difference in mean daily dose between the ethnic groups, but the small numbers preclude further analysis. The glipizide group had a larger percentage increase in dose within the first year than did the glyburide group; however, the percentage increase from the 3-month dose was similar after 18 months (22.7 percent glyburide, 27.5 percent glipizide.) Average daily cost of therapy, based on mean daily dose, was slightly lower for glyburide-treated patients.

CONCLUSIONS

If glycemic control is similar with glyburide and glipizide, as seen in this study, economic considerations regarding choice of therapy and formulary inclusion may be appropriate.