Centre for Evidence-based Veterinary Medicine

Bias in veterinary clinical trials

Pure filtered evidenceRandomised controlled trials (RCTs) are an important source of evidence in veterinary medicine when trying to make decisions about treatments. But what is the quality of veterinary RCTs, and does the funding source of a trial influence its results?

The aims of this work are:

1. To examine the relationship between funding source and positive outcome reporting in veterinary RCTs, and
2. To assess the scope and quality of published veterinary RCTs.

We have searched the literature via PubMed for RCTs published in 2011 relating to five species (cats, dogs, cattle, horses and sheep).

For all trials that involved a pharmaceutical intervention we then extracted several pieces of information:

  1. The outcomes the authors set out to measure and whether the treatment of interest had a positive, negative or no effect on the outcomes;
  2. The funding source for the study;
  3. A basic assessment of study quality, including identifying potential sources of bias.

The data has been analysed to examine whether there is a relationship between the funding source of a trial and the likelihood of the trial reporting a "positive" outcome.  Two papers have been written up from this work and have now been published:


Kathryn Wareham, Rachel Dean, Douglas Grindlay, Marnie Brennan, Bobby Hyde

Centre for Evidence-based Veterinary Medicine

School of Veterinary Medicine and Science
University of Nottingham, Sutton Bonington Campus
Leicestershire, LE12 5RD

Tel: +44 (0) 115 951 6576
Fax: +44 (0) 115 951 6415
Email: CEVM@nottingham.ac.uk