Dear All.
The Effective Practice and Organization of Care Group of Cochrane
(http://www.epoc.uottawa.ca/aboutus.htm) may be a good place to start
looking for info. This Cochrane Review Group certainly consider
before-after and interrupted time series as source of evidence.
At a recent Cochrane meeting I attended a thought provoking talked by
Dr. Ian Shrier on the validity of different inclusion criteria for
systematic reviews, I am forwarding this e-mail to him and hopefully he
can give us an important input.
Thank you.
Kukuh
Kukuh Noertjojo, MD MHSc MSc
Evidence Based Practice Group,
Clinical Services, Worker and Employer Services
WorkSafe BC
6951 Westminster Highway
Richmond, BC V7C 1C6
CANADA.
Phone: 604 231 8417
Fax: 604 279 7698
-----Original Message-----
From: Evidence based health (EBH)
[mailto:[log in to unmask]] On Behalf Of Olive Goddard
Sent: Thursday, December 01, 2005 2:23 AM
To: [log in to unmask]
Subject: Re: Using CEBM's Levels of Evidence to rate linkages between
animal and human health
Dear Colleagues,
Does anyone have any comments on the following.
All good wishes,
Olive
Olive Goddard
Centre and Editorial Manager
Centre for Evidence-Based Medicine
Room 116
Institute of Health Sciences
Old Road Campus, Headington
Oxford, OX3 7LF
.....................................................................
Tel: +44 (0)1865 226991 email: [log in to unmask]
Fax: +44 (0)1865 226845 web: www.cebm.net
Mobile: 0773 484 2403 web: www.cebmh.com
>>> "Mark Johnston" <[log in to unmask]> 11/29/05 3:35 pm >>>
Here are some observations which may serve to stimulate further
discussion,
although they are mostly methodological rather than specific to your
project.
The study of environmental toxins is an area in which RCTs are not
going to be conducted.
It is not that the CEBM hierarchy is irrelevant: it is that non-RCT
elements need to be
examined and strengthened.
It seems to me that two sources of evidence would be relevant:
i) correlational evidence (in this case on human-animal health
associations;
ii) extrapolations from more controlled studies and laboratory
studies.
One would expect that theory would be relevant (e.g. animals are
similar to humans
in some ways but not others). I suspect that it would be better to
explicate the
theory or alternative theories rather than to ignore the matter.
Better studies would test alternative explanations for an association;
weaker studies would not.
Time series data become important or critical. If one had good data
on
human-animal health
over time (with a sufficiently large number of points that statistical
stability can be established) and f
there is a sudden event (e.g. release of a toxin in the environment),
then one could in
principle detect the effect of the toxin quantitatively. You are
probably aware of such
designs. Rarely are data sufficient to implement such a study, but if
good data
were available and alternative explanations ruled out, then convincing
(level 1 or 1.5?) or highly
probable (level 2?) conclusions could be drawn.
In sum, there is a need to augment the standard hierarchy to be more
sensitive or explicit
regarding correlational and modeling designs, so that one can more
precisely distinguish stronger
from weaker alternative research designs.
Best regards to all.
Mark V. Johnston, Ph.D.
Director of Outcomes Research, KMRREC,
Professor, Physical Medicine & Rehabilitation, UMDNJ/NJMS,
1199 Pleasant Valley Way,
West Orange, NJ 07052
Phone: 973 243 6810
Fax: 973 243 6963 R.A.: 973 243 6876
>>> Olive Goddard <[log in to unmask]> 11/23/2005 6:39 AM >>>
Dear Colleagues,
I posted the following on the EBH list a little while ago. However,
the author did not receive any replies, although I am sure several
were
posted. I have now added Peter Rabinowitz to the EBH list so would be
grateful if you would respond again.
As per our policy, I have not attached the manuscript. If you would
like a copy would you contact Peter Rabinowitz directly.
All good wishes,
Olive
"Dear Mrs. Goddard,
"I am a faculty member at the Yale University School of Medicine, and
a
great admirer of the work of your Centre. I am a member of a group
engaged in a project funded by the National Library of Medicine to
assess the scientific evidence regarding the use of animals as
'sentinels' of human environmental health hazards. Our group of human
and animal health professionals are trying to critically determine the
strength of evidence linking animal and human health in a number of
instances. In recent years, there has been increasing discussion of
ways to bridge scientific gaps between animal health and human health
professionals. We are trying to build on Evidence Based Medicine
principales in this effort, although we realize that it is stretching
the concept a bit.
"At the suggestion of Mark Ebell, MD, a physician in the U.S. who has
helped develop the S.O.R.T. taxonomy for patient oriented evidence, we
have tried to adapt the Centre for Evidence-based Medicine's Levels of
Evidence to our task of comparing human and animal health
exposure-outcome relationships. The attached draft manuscript gives
an
example of our approach
"I would be extremely grateful if one or more members of your Centre
could give us some feedback on what we are trying to do - does it seem
appropriate to try and use the Centre's Levels of Evidence as we are
doing in the attached ms? Is there another rating scheme that would
fit
our needs better - or should we invent our own? Our preference is not
to reinvent the wheel, but we also want to respect the scope and
purpose
of the toods you have developed.
"Any input to our process, no matter how critical, would be greatly
appreciated. For further background on our project, please see our
website http://canarydatabase.org
"Gratefully,
Peter Rabinowitz MD MPH
Associate Professor Medicine
Yale University School of Medicine
Yale Occupational and Environmental Medicine Program
135 College Street, 3rd Floor
New Haven, CT 06510
Tel 203-785-5885
Fax 203-785-7391
[log in to unmask]"
Olive Goddard
Centre and Editorial Manager
Centre for Evidence-Based Medicine
Room 116
Institute of Health Sciences
Old Road Campus, Headington
Oxford, OX3 7LF
.....................................................................
Tel: +44 (0)1865 226991 email: [log in to unmask]
Fax: +44 (0)1865 226845 web: www.cebm.net
Mobile: 0773 484 2403 web: www.cebmh.com
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