Risk of Bias in Randomized Controlled Trials Published in Iranian Nursing and Midwifery Journals in 2010



Mohammady M¹ ; Adoli S² Show Affiliations
Source: Iranian Journal of Epidemiology Published:2014

Abstract

Background & Objectives: Randomized controlled trials are the most reliable type of study to be able to compare different interventions in scientific research. The introduction of bias into the design and conduct of randomized controlled trials can seriously affect the accuracy of the results and led to the results be invalid. The aim of this study was to assess the bias in randomized controlled trials published in Iranian nursing and midwifery journals. Methods: We searched all published articles in eight professional nursing and midwifery Iranian journals in 2010. Risk of bias in RCTs was assessed using of Cochrane group risk of bias standard tool by two reviewers independently. Results: After reviewing the eight journals, 68 randomized controlled trials were retrieved. The majority of studies had unclear or high risk of bias. Random sequence generation in 22%, concealment allocation in 4.5%, blinding in 22%, incomplete outcome data in the 35.3%, selective outcome reporting in 51.5%, and other bias in 36.7% of the studies were in low risk of bias. Conclusion: A large proportion of the studies had high or unclear risk of bias. It was considerable that none reporting bias led to uncertainty reader from study quality. Bias might significantly affect the internal validity of the studies results; therefore in interpretation of the findings of these studies caution should be taken.