Sample size and number of outcome measures of veterinary randomised controlled trials of pharmaceutical interventions funded by different sources, a cross-sectional study

Wareham, Kathryn and Hyde, Robert and Grindlay, Douglas J.C. and Brennan, Marnie L. and Dean, Rachel S. (2017) Sample size and number of outcome measures of veterinary randomised controlled trials of pharmaceutical interventions funded by different sources, a cross-sectional study. BMC Veterinary Research, 13 . 295/1-295/9. ISSN 1746-6148

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Abstract

Background

Randomised controlled trials (RCTs) are a key component of the veterinary evidence base. Sample sizes and defined outcome measures are crucial components of RCTs.

To describe the sample size and number of outcome measures of veterinary RCTs either funded by the pharmaceutical industry or not, published in 2011.

Methods

A structured search of PubMed identified RCTs examining the efficacy of pharmaceutical interventions. Number of outcome measures, number of animals enrolled per trial, whether a primary outcome was identified, and the presence of a sample size calculation were extracted from the RCTs. The source of funding was identified for each trial and groups compared on the above parameters.

Results

Literature searches returned 972 papers; 86 papers comprising 126 individual trials were analysed. The median number of outcomes per trial was 5.0; there were no significant differences across funding groups (p = 0.133). The median number of animals enrolled per trial was 30.0; this was similar across funding groups (p = 0.302). A primary outcome was identified in 40.5% of trials and was significantly more likely to be stated in trials funded by a pharmaceutical company. A very low percentage of trials reported a sample size calculation (14.3%).

Conclusions

Failure to report primary outcomes, justify sample sizes and the reporting of multiple outcome measures was a common feature in all of the clinical trials examined in this study. It is possible some of these factors may be affected by the source of funding of the studies, but the influence of funding needs to be explored with a larger number of trials. Some veterinary RCTs provide a weak evidence base and targeted strategies are required to improve the quality of veterinary RCTs to ensure there is reliable evidence on which to base clinical decisions.

Item Type: Article
Keywords: Quality; Primary outcome; Study design and data analysis; Clinical trials; Evidence based medicine
Schools/Departments: University of Nottingham, UK > Faculty of Medicine and Health Sciences > School of Medicine > Division of Rheumatology, Orthopaedics and Dermatology
University of Nottingham, UK > Faculty of Medicine and Health Sciences > School of Veterinary Medicine and Science
Identification Number: 10.1186/s12917-017-1207-0
Depositing User: Eprints, Support
Date Deposited: 14 Nov 2017 09:11
Last Modified: 18 Nov 2017 05:28
URI: http://eprints.nottingham.ac.uk/id/eprint/48115

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