Treatment choice and effectiveness of adding sulphonylurea or glitazones to metformin for the treatment of type 2 diabetes mellitus.
OBJECTIVE
This study investigates the treatment choice between, and the effectiveness of, adding sulphonylurea or glitazone to ongoing metformin therapy for patients with type 2 diabetes mellitus in the clinical practice setting.


METHODS
A multicentre observational study using data from clinical records was conducted in Finland, France, Germany, Norway, Poland, Spain and the UK. Data were collected for patients who added sulphonylurea or glitazone to metformin. Effectiveness was defined as a change in haemoglobin A1c (HbA(1c)) from baseline to approximately 1 year after the initiation of additional therapy. To allow for comparisons between the two medication regimens, propensity score matching was employed. Treatment choice was analysed using a probit regression model. We hypothesized that treatment choice was associated with factors reflecting patient's characteristics, patient's experience with diabetes, patient's health or to physician's characteristics at baseline.


RESULTS
Compared with baseline, adding sulphonylurea to metformin reduced HbA(1c) by 0.8% (p < 0.0001), while adding glitazone to metformin reduced HbA(1c) by 0.9% (p < 0.0001). Percentage at HbA(1c) goal (6.5%) increased from 6.9 to 23.8% for the sulphonylurea group and 8.3 to 33.3% for the glitazone group. Both groups had similar changes in high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides. In the probit regression model, age, HbA(1c), weight, treatment for weight reduction, history of macrovascular complications and type of physician were significant factors associated with treatment choice.


CONCLUSIONS
This study is consistent with the results of long-term randomized clinical trials in a clinical practice setting. Both regimens were able to reduce HbA(1c) by about 1%.
Stargardt
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T
Department of Health Care Management, WHO Collaborating Centre for Health Systems Research and Management, University of Technology, Berlin, Germany. tom.stargardt@tu-berlin.de
Yin
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DD
Alexander
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CM
D000368:Aged; D002755:Choice Behavior; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D005060:Europe; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D013453:Sulfonylurea Compounds / Q000008:administration & dosage*; D045162:Thiazolidinediones / Q000008:administration & dosage*; D016896:Treatment Outcome
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin; D013453:Sulfonylurea Compounds; D045162:Thiazolidinediones