Are concomitant treatments confounding factors in randomized controlled trials on intensive blood-glucose control in type 2 diabetes? a systematic review

作者：Boussageon Remy; Supper Irene; Erpeldinger Sylvie; Cucherat Michel; Bejan Angoulvant Theodora; Kassai Behrouz; Cornu Catherine; Gueyffier Francois^*

来源：BMC Medical Research Methodology, 2013, 13(1): 107.

DOI：10.1186/1471-2288-13-107

• Blood glucose
• Concomitant treatment
• Observer bias
• Randomized controlled trial
• Type 2 diabetes mellitus

Background: Open-label, randomized controlled trials (RCTs) are subject to observer bias. If patient management is conducted without blinding, a difference between groups may be explained by other factors than study treatment. One factor may come from taking concomitant treatments with an efficacy on the studied outcomes. In type 2 diabetes, some antihypertensive or lipid-lowering drugs are effective against diabetic complications. We wanted to determine if these concomitant treatments were correctly reported in articles of RCTs on type 2 diabetes and if they might have influenced the outcome. %26lt;br%26gt;Methods: We performed a systematic review using Medline, Embase, and the Cochrane Library (from January 1950 to July 2010). Open-label RCTs assessing the effectiveness of intensive blood-glucose control in type 2 diabetes were included. We chose five therapeutic classes with proven efficacy against diabetes complications: angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor antagonists (AIIRAs), fibrates, statins, and aspirin. Differences between concomitant treatments were considered statistically significant when p %26lt; 0.05. %26lt;br%26gt;Results: A total of eight open-label RCTs were included, but only three (37.5%) of them published concomitant treatments. In two studies (ACCORD and ADVANCE), a statistically significant difference was observed between the two groups for aspirin (p = 0.02) and ACEIs (p = 0.02). %26lt;br%26gt;Conclusions: Few concomitant treatments were published in this sample of open-label RCTs. We cannot completely eliminate an observer bias for these studies. This bias probably influenced the results to an extent that has yet to be determined.

• 出版日期2013-8-30