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.
Sackler School of Medicine, Tel Aviv University, Israel. loebst_r@mac.org.il
Ronen
R
Loebstein
Itzhak
I
Katzir
Janet
J
Vasterman-Landes
Hillel
H
Halkin
Yossef
Y
Lomnicky
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