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ICGS with a symposium on WGA guidelines on the design and reporting of glaucoma surgical trials
April 16-18, 2009, Geneva, Switzerland
Tarek Sharaawy, Geneva, Switzerland
One of the main highlights of this meeting was the ICGS symposium on
the WGA guidelines. This coincided with the publication, on the same occasion,
of the guidelines in its printed form.* The symposium drew an impressive
crowd of glaucoma specialists, as well as representatives of the glaucoma
industry, and specifically from companies currently promoting glaucoma surgical
technologies. The symposium was chaired and moderated by Mark Sherwood,
one of the three main editors of the guidelines. The first talk was an overview
by Tarek Shaarawy, another editor of the guidelines, on the main recommendations,
including issues related to how glaucoma surgical complications should be
reported, statistical methods required, and relevant economic analysis.
He also summarized recommendations related to required methodology. Such
recommendations included that the surgeon who performs the procedure
should not evaluate the patient for the purpose of providing information
that will be used to judge the success or failure of the procedure.
He reiterated the guidelines recommendations that regard the randomized
clinical trial as the most valid methodology to determine the safety
and efficacy of new glaucoma surgical procedures and to compare their results
and complications with those of established glaucoma surgical techniques.
Ethical considerations on how to conduct such trials were also discussed,
and he drew attention to the fact that the guidelines also include,
as an appendix, a complete blueprint on how research protocols should
prepared and managed. This should greatly help newcomers as well as
veteran researchers in this dynamic field. This was followed by Franz Grehn,
the third and last editor, on how to graphically present the study data
and results. In addition to survival curves, the guidelines introduced the
concept of mandatory scatter plots as a useful tool for unveiling raw
data and opening the way to possibilities regarding re-analysis of
data for future comparisons. Keith Barton reported on the guidelines recommendations
regarding definitions of success. IOP reduction was acknowledged as the
principle end-point of surgical trials. The Guidelines calls for robust
baseline IOP documentation and consistent IOP. It recommended that
pre- and post-operative numbers of medications should be enumerated as the
total number of classes of hypotensive drugs being used. Definitions
of success should be clearly stated in trial design and should include an
upper and lower limit. These may include more than one upper limit
or a combination of an upper limit and a percentage reduction. Graphical
representation of success should clearly illustrate the number of patients
still in the trial at a particular time-point. The patients, who have
achieved a particular end-point without additional hypotensive medications,
should be distinguishable from those who have required medications.
Visual field data should be reported where possible, although the practicality
of using visual field data as a primary outcome measure is limited in surgical
trials for a number of reasons.
This was followed by a dynamic discussion between the participants and the
presenters, in which further clarifications were offered regarding specific
details of the guidelines. Mark Sherwood expressed, on behalf of the authors,
their hope and aspiration in as wide as possible adoption of such guidelines
as a common language between researchers in this vital field.
*The guidelines are published by Kugler Publications, and can be ordered here
