This Article  • Full text PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Contact me when this article is cited  Related Content  • Similar articles in this journal  Social Bookmarking   What's this?

Salim Daya, MB, MSc; Khalid S. Khan, FCPS; Alejandro R. Jadad, MD, DPhil
Hamilton, Ontario

Arch Intern Med. 1997;157(3):357-358.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

We would like to respond to the questions raised by Laupacis regarding our article on the importance of the quality of primary studies in producing unbiased systematic reviews. We have now reanalyzed our data using logistic regression, with pregnancy as the dependent variable, to assess the impact of study quality on treatment effect. The value of the β coefficient for the interaction between the variables "study quality" and "treatment allocation" provided an estimate of the amount of bias and was tested formally against the null hypothesis that the β coefficient is 0 or its exponent (OR) is 1.0. We observed that for trials of low quality the treatment effect was significantly higher than 1.0 (OR, 4.22; 95% CI, 1.42-12.50; P=.008), indicating that the treatment effect was overestimated by such trials. This relationship between studies of poor quality and exaggeration of treatment effect estimation has been reported by several other investigators . . . [Full Text PDF of this Article]

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?