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Research
Searching for evidence for systematic reviews of volume-outcome relationships in peripheral vascular surgery.
Helen Buckley Woods, Patrick Phillips, Edith Poku, Munira Essat, Edward A. Goka, Jonathan Michaels, Simon Palfreyman, Suzy Paisley, Eva C Kaltenthaler , Phil Shackley
Introduction
A recent vascular services research project explored the relationship between volume and outcome in peripheral vascular surgery, through a series of systematic reviews. The reviews were an update of a previous review
(Michaels et al, 2000). Particular searching methods and ways of working emerged as the most effective approaches to identify evidence. Iterative searching methods were most appropriate, as it was not possible or practical to create one, a-priori search strategy with the aim of identifying all the relevant literature. A multi-disciplinary team approach to developing search strategies was chosen and facilitated by the use of collaborative web tools.
Methods
Searching was conducted as one process, with papers subsequently selected for each individual population e.g. carotid artery disease. There were three search iterations for the project. Search one aimed to identify papers for an overview of systematic reviews and was based on the main search strategy of the original review (Michaels et al, 2000); it combined terms for vascular conditions and volume of surgery. The second search extended the initial search to identify primary studies and included additional synonyms for surgical procedures.
After the results of both searches were examined the team returned to the original review
to see if all the included studies had been retrieved. This was to give an indication of
where further evidence might lie. The consultation of these papers indicated that
key concepts were described in an alternate way in the literature and that a new search,
focused on specific surgical procedures and patient outcomes could uncover new evidence.
Therefore, keywords and index terms from these papers formed the basis for a new (third)
search. In order to improve the sensitivity of the search the information specialist invited the
rest of the team to contribute keywords and MeSH. As two experienced clinicians were part
of the project team this was a crucial step and facilitated quickly by the use of a web document shared within the team. This search identified 7 of the 29 included studies for the current reviews. Finally, reference and citation searching, in addition to searches of five key conference proceedings were undertaken, which also retrieved relevant studies.
Results
An iterative and multifarious approach to identifying evidence is the most beneficial when the review concepts are not described in a standardised manner. This allows many access points to relevant literature. Multi-disciplinary working is central to supporting this type of non-linear search approach.
Conclusions
Multi-disciplinary working within a systematic review team facilitates a more efficient use of time and utilizes technical expertise and subject knowledge at an optimum level. The use of new technology can augment this process. Using a staged approach to identifying evidence alongside commonly used techniques, such as citation tracking , is a pragmatic approach to this type of review. This approach could be tested alongside data mining methods in order to review effectiveness of retrieving relevant studies and the associated staff time taken to complete these processes.
Funding and disclaimer: This poster presents independent research funded by the National Institute for Health Research (NIHR) under the Programme Grants for Applied Research programme (RP-PG ). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.
Michaels J., Brazier J., Palfreyman S., Shackley P. and Slack R. (2000).  Cost and outcome implications of the organisation of vascular services. Health Technology Assessment, 4.
Picture credit: Scott Maxwell ( via Flickr CC BY-SA 2.0