Intervention to Decrease Glyburide Use in Elderly Patients With Renal Insufficiency⁎

Objectives

The objectives of this study were to describe changes in glyburide prescribing in cohorts that were and were not targeted by a risk reduction project, assess factors associated with glyburide discontinuation, and evaluate changes in glycated hemoglobin (ie, HbA_1c) levels and rates of serious hypoglycemia.

Methods

This historical cohort study included a targeted cohort of 4368 outpatient veterans aged ≥65 years with active prescriptions for glyburide between April 1, 2007 and June 30, 2007 and serum creatinine (SCr) ≥2 mg/dL and a nontargeted cohort of 1886 outpatients meeting these same criteria between July 1, 2007 and September 3, 2007. The intervention in the risk reduction project took place on September 4, 2007 and entailed giving regional pharmacy leaders information about the increased risk of hypoglycemia with glyburide and the list of targeted patients for follow up with providers. For each patient, the study period was the time between the date they first met the eligibility criteria and March 31, 2008. All data were obtained from Veterans Affairs (VA) administrative databases. The primary outcome was the discontinuation of glyburide. Secondary outcomes were the change in HbA_1c after stopping glyburide and the rate of serious hypoglycemia after intervention.

Results

Incidence rate ratios (IRRs) for glyburide discontinuation in targeted versus nontargeted cohorts were statistically significantly elevated in September (IRR 2.1; 95% CI 1.7–2.5), October (IRR 1.3; 95% CI 1.1–1.6), and November 2007 (IRR 1.4; 95% CI 1.1–1.7). The intervention, black race, SCr, Charlson comorbidity score, new glyburide use, and VA region were independently associated with discontinuation. Among patients in the targeted cohort who discontinued glyburide, mean (SD) HbA_1c at baseline and after discontinuation were 7.17% (1.35%), and 7.22% (1.34%), respectively (P = 0.36). The hypoglycemia rates/1000 person-days were 0.093 before the intervention and 0.070 afterwards (P = 0.10).

Conclusion

A one-time intervention in a risk reduction project decreased glyburide use over a 3-month period in elderly outpatients with renal insufficiency without compromising glucose control.