OBJECTIVE: To evaluate treatment patterns associated with diabetes medication regimen changes after hospitalization on the basis on preadmission hemoglobin A1c levels. METHODS: In this retrospective database analysis, patients with a diabetes diagnosis, hospitalization, and documented hemoglobin A1c level within the 90 days leading up to hospital admission were identified in an administrative claims database. Treatment regimens were assessed before and after hospitalization. The proportion of patients who had progression, reduction, or no change in therapy was compared across hemoglobin A1c subgroups: hemoglobin A1c <7.0%, hemoglobin A1c 7.0%-7.9%, and hemoglobin A1c >/=8.0%. RESULTS: Four hundred patients were included (192 in hemoglobin A1c <7.0% group, 94 in hemoglobin A1c 7.0%-7.9% group, and 114 in hemoglobin A1c >/=8.0% group). Demographically, hemoglobin A1c subgroups did not differ significantly (mean age, 57 years; 47.5% male). With respect to therapeutic regimen overall, 28%, 24%, and 48% of patients experienced progression, reduction, and no change, respectively. Across hemoglobin A1c subgroups, 37.7% of patients in the hemoglobin A1c >/=8.0% subgroup had therapy progression compared with 26% and 20.2% in the hemoglobin A1c <7.0% and hemoglobin A1c 7.0%-7.9% subgroups, respectively (P = .032 and P = .006, respectively). Within the progression category, progression via insulin initiation was significantly higher in the hemoglobin A1c >/=8.0% subgroup (55.8%) than in the hemoglobin A1c <7.0% subgroup (16%, P<.001), but not significantly higher than in the hemoglobin A1c 7.0%-7.9% subgroup (36.8%, P = .084). In the hemoglobin A1c >/=8.0% subgroup, a lower percentage of patients, 35.1%, experienced no therapy change than in both the hemoglobin A1c <7.0% subgroup (52.6%) and the hemoglobin A1c 7.0%-7.9% subgroup (54.3%) (P = .003 and P = .006, respectively). There was no difference between subgroups in reduction of therapy. CONCLUSIONS: A higher proportion of patients with a hemoglobin A1c level >/=8.0% had progression of their antidiabetes therapy after hospitalization and fewer patients had no change in therapy than those in lower hemoglobin A1c subgroups. These data suggest that clinicians may be using hemoglobin A1c measurements to guide discharge planning treatment decisions.