Database assessment of the effectiveness of brand versus generic rosiglitazone in patients with type 2 diabetes mellitus.
BACKGROUND
To compare the effectiveness of brand rosiglitazone maleate (BRM) versus generic rosiglitazone HCl (GRH) in patients with type 2 diabetes mellitus, using computerized records of a healthcare organization. Retrospective, longitudinal database analysis.


METHODS
Comparison of HbA1C reduction in patients starting treatment with either BRM (n=740) or GRH (n=306) in the years 2004-2005.


RESULTS
BRM users were older (63.5+/-11 vs. 61.7+/-10 years p<0.001) and presented more cardiovascular disorders (38% vs. 25%, p<0.001) with no differences in gender distribution, rates of hypertension or use of concomitant oral hypoglycemic drugs. Use of concomitant insulin was more frequent (17.7% vs. 6.2%, p<0.0001), rates of dispensed rosiglitazone doses >4 mg/d (65.3% vs. 48.5%, p<0.001) and treatment duration was longer (9.3+/-6.2 vs. 5.2+/-2.2 months, p<0.001) with the generic formulation. Baseline HbA1C levels were higher (9.0+/-1.5 vs. 8.6+/-1.2%, p<0.001) and the absolute decrease in HbA1C levels was greater in the GRH group (-1.2+/-1.6% vs. -0.5+/-1.7%, p<0.001). On multiple regression analysis, the decrease in HbA1C (dependent variable) was associated mainly with initial HbA1C level (partial r2=0.30). Rosiglitazone formulation (partial r2=0.02), age, treatment duration and concomitant insulin (partial r2=0.006) were all significant but minor predictors, with no effect of rosiglitazone daily dose. Mean regression-predicted decreases in HbA1C (with 95% CL) were not significantly different between the two rosiglitazone formulations: -1.6% (-4.3% to +1.1%) for GRH and -1.1% (-3.8% to +1.6%) for BRM.


CONCLUSIONS
In this retrospective database analysis, we found no evidence of different effectiveness of generic vs. brand rosiglitazone in lowering HbA1C levels.
Loebstein
Ronen
R
Sackler School of Medicine, Tel Aviv University, Israel. loebst_r@mac.org.il
Katzir
Itzhak
I
Vasterman-Landes
Janet
J
Halkin
Hillel
H
Lomnicky
Yossef
Y
D019992:Databases as Topic; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000627:therapeutic use*; D016896:Treatment Outcome
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D000077154:Rosiglitazone; D045162:Thiazolidinediones