An observational study of the effect of two thiazolidinediones on blood lipid levels: Rosiglitazone and pioglitazone in routine clinical practice

Background: Rosiglitazone maleate and pioglitazone hydrochloride are established antihyperglycemic agents that are effective when used as monotherapy or in combination with other medications. However, the data regarding the effects of these agents on blood lipid levels are contradictory. Objective: The aim of this study was to determine whether the use of rosiglitazone and pioglitazone in clinical practice is associated with any changes in blood lipid levels. Methods: A retrospective chart review using electronic medical record data was conducted of patients with type 2 diabetes mellitus who were newly treated with either rosiglitazone or pioglitazone and had 1 lipid measurement within 6 months prior to and 12 months following initial thiazolidinedione (TZD) therapy. Outcome measures were mean changes in low- and high-density lipoprotein cholesterol (LDL-C and HDL-C, respectively). To control for differences in baseline characteristics and/or selection bias, the treatment cohorts were compared using multivariate statistical techniques. Results: A total of 371 patients were included in the study; the pioglitazone cohort comprised 148 patients (82 women, 66 men; mean [SD] age, 64.9 [10.8] years) and the rosiglitazone cohort comprised 223 patients (113 men, 110 women; mean [SD] age, 66.1 [11.9] years). Pioglitazone-treated patients had a statistically higher mean baseline LDL-C compared with rosiglitazone-treated patients (125.0 mg/dL vs 116.6 mg/dL; P = 0.04). On average, LDL-C levels decreased over the study period, with no significant differences between the 2 cohorts (9.9 mg/dL vs 4.3 mg/dL for pioglitazone and rosiglitazone, respectively), although changes in both cohorts were statistically significant (P < 0.001). Conclusions: TZD therapy appears to be associated with a small decrease in LDL-C within the first 6 months after initiation. No differences in changes in LDL-C or HDL-C could be discerned between patients treated with rosiglitazone compared with pioglitazone. Copyright (C) 2004 Excerpta Medica, Inc.