FDA warning and removal of rosiglitazone from VA national formulary.

OBJECTIVES: To describe changes in rosiglitazone prescribing following the US Food and Drug Administration (FDA) warning of potentially increased risk of myocardial infarction and removal from the Department of Veterans Affairs National Formulary (VANF), assess patient-level factors associated with rosiglitazone discontinuation, and evaluate changes in glucose control. STUDY
DESIGN: Historical cohort.
METHODS: Veterans with an active outpatient prescription for rosiglitazone on April 1, 2007, were followed until June 30, 2008. Incidence rate ratios (IRRs) of rosiglitazone discontinuation were compared over time using Poisson methods. We identified patient-level factors associated with stopping rosiglitazone using multivariable Poisson regression and compared glycated hemoglobin (A1C) values across time among patients who discontinued/continued rosiglitazone using linear mixed models.
RESULTS: Of 95,539 veterans with an active outpatient rosiglitazone prescription, 86.7% discontinued rosiglitazone. Discontinuation rates increased significantly after the FDA warning, with IRRs from 1.6 to 1.8. After removal from the VANF, rosiglitazone discontinuation rates again increased significantly. Discontinuing rosiglitazone was associated with the FDA warning, removal from the VANF, female sex, black race, Hispanic ethnicity, comorbidity, A1C greater than 9%, and use of rosiglitazone as first- or second-line therapy. Among patients who did and did not receive a replacement medication, the mean changes in A1C from baseline were 0.12% and 0.46%, respectively. For those who continued rosiglitazone, the mean change in A1C was -0.02%.
CONCLUSION: The rosiglitazone discontinuation rate increased following the FDA warning and increased further following removal of rosiglitazone from the VANF. Glucose control may have declined among those who discontinued rosiglitazone.