Badri,
To your panel discussant who was skeptical of the literature you could
have replied that yes, cherrypicking a single article from the
literature is dangerous. That is why one needs to do an evidence-based
systematic review, and if multiple articles are available, a
meta-analysis. There are three common scenarios that can mislead in the
abscence of a meta-analysis.
1) Simply vote-counting a predominance of positive findings is subject
to publication bias. A good meta-analysis may (but not invariably)
indicate the presence or absence of publication bias.
2) Simply vote counting a predominance of negative findings is
misleading, if the negative findings are actually findings of "no
statistical significance" in small studies of low power. A
meta-analysis of such low-power studies may find a significant positive
effect.
3) An inconclusive finding of mixed results in the literature may be
misleading if many of the "negative" findings are actually findings of
"no statistical significance" in small studies of low power. Again, a
systematic review and meta-analysis may show that the findings are
mostly in the positive direction, and become statistically significant
when the meta-analysis provides the necessary power.
Guidelines may or may not be based on systematic reviews, and they are
published infrequently, and so may be behind the available literature.
Good luck in the future, and I hope this helps.
David L. Doggett, Ph.D.
Senior Medical Research Analyst
Health Technology Assessment and Information Services
ECRI, a non-profit health services research organization
5200 Butler Pike
Plymouth Meeting, Pennsylvania 19462, U.S.A.
Phone: (610) 825-6000 x5509
FAX: (610) 834-1275
http://www.ecri.org
e-mail: [log in to unmask]
-----Original Message-----
From: padmanabhan badrinath [mailto:[log in to unmask]]
Sent: Monday, February 04, 2002 12:29 PM
To: [log in to unmask]
Subject: Evidence in journals?
Dear All,
Greetings from Al-Ain the oasis city. This morning I presented a seminar
titled "Aids, past, present & future" in the "AIDS - Update" organised
by
our health district. Over 150 health professionals attended. There were
presentations on AIDS epidemiology, management, basic research etc at
the
update. In the panel discussion a question was raised by a member of the
audience. Is there any data to show the harms/benefits to the infants of
HIV
infected mothers if the babies are breastfed? I mentioned the results of
this trial from JAMA.
Morbidity and mortality in breastfed and formula-fed infants of
HIV-1-Infected women. A randomised clinical trial. Mbori-Ngacha D,
Nduati R
et al. JAMA. 2001;286:2413-2420
The paediatrician (a senior clinician and an academic)in the panel
immediately responded. "In journals you can find what ever you are
looking
for. If you are looking for a donkey you will find it. If you are
looking
for a monkey you will find it. I only use CDC or AAP guidelines".
I did not pick up an argument with him in front of the audience and kept
quite. Any thoughts on how I should have handled the situation?
Cheers & regards,
Badri
Dr.P.Badrinath M.D.,M.Phil.,(Epid) PhD(Cantab)DFPHM(UK).,MPH(Distinc)
Clinical Assistant Professor & Hon Consultant in Preventive Medicine,
Department of Community Medicine,
UAE University, PO Box 17666, Al Ain,
United Arab Emirates.
Tel: 00 971 3 7039 652
Fax: 00 971 3 7672022.
http://myprofile.cos.com/badrishanthi
"For an excellent review of the current medical literature, go to
Journals
Scan www.uaeu.ac.ae/jscan/" - BMJ 3rd June 2000, Netlines
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