In its evidence-based guidelines for type 2 diabetes (1), the Veterans Health Administration (VHA) recommends a second-generation sulfonylurea or metformin as first-line drug therapy. Metformin or sulfonylurea is added to the first agent if HbA1c (A1C) control is not satisfactory. Because of their modest effect on A1C, unknown long-term safety, and high cost, the VHA recommends reserving thiazolidinediones (glitazones) for selected patients. We compared community versus Veterans Affairs (VA) primary care providers regarding initiation of glitazone therapy and presence of contraindications in veterans, who frequently obtain care both within and outside the VHA.
Glitazone prescription at the Birmingham VA Medical Center (BVAMC) required endocrinology consultation in fiscal year 2002. Using the VHA’s electronic medical record, we identified all consultations to the BVAMC endocrinology service in fiscal year 2002 and performed structured chart review. We assessed adherence to then-current guidelines for glitazone use, including 1) failure of combination metformin-sulfonylurea therapy and patient refusal of insulin or 2) insulin dose >75 units/day and A1C >1% above target.
We noted whether glitazone therapy was started by private physicians (110 patients) or by a request originating from within the VHA (65 patients). These two patient groups did not differ significantly in age, sex, or duration of diabetes. Insulin was tried before glitazone was initiated in 28% of patients treated within the VHA and 19% of those treated outside the VHA (P = 0.178). VHA physicians were more likely than community practitioners to have tried a metformin-sulfonylurea combination before rosiglitazone (74.4 vs. 44.4%, P = 0.0005). Of patients started on rosiglitazone within the VHA, 48.9% had A1C improvements of <0.5% (information unavailable for community physicians). However, VHA physicians used maximum rosiglitazone doses in only 17% of patients compared with 29% outside VHA. Heart failure was present in 12% of patients when rosiglitazone was requested, with no difference between community and VHA physicians in failing to recognize this contraindication (P = 0.813). From clinic notes, medication costs were the reason for seeking VHA care in 52% of patients whose glitazone had been initiated outside the VHA.
The differences between VHA and community physicians in initiating thiazolidinedione therapy may reflect differences in prescribing patterns across different systems. However, individuals treated in the community who found glitazones prohibitively expensive might have sought out the VHA. As we did, but in a more general population, Lederle and Parenti (2) documented that over half of veterans transferring to the VHA from community health care did so because of drug costs. Patients on less costly hypoglycemic regimens might be less likely to seek dual care. Therefore, we cannot easily extrapolate our findings to the entire private sector. Of note, medication costs contribute to poorer glycemic control in individuals with chronic illnesses (3). Piette et al. (4) found more medication underuse in patients with limited or no medication insurance than in VHA users.
In summary, we found that requests for initiating rosiglitazone were more guideline concordant when originating from within the VHA than from community physicians but that contraindications were not always recognized by either source. These expensive medications, the long-term safety of which is still unknown, may be significantly overused.
