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By David A. Grimes, MD
FHI Vice President of Biomedical Affairs
Dr. Grimes is an obstetrician/gynecologist with training in public
health. A former member of the U.S. Preventive Services Task Force, he
is a student of and advocate for evidence-based medicine. With FHI
colleagues, he is conducting Cochrane reviews in the area of fertility
regulation.
Each year, some 25,000 biomedical journals publish millions of
articles. Abstracts from more than 12 million of these articles are
already archived and free through PubMed
to anyone in the world with an Internet connection. Regrettably, many
developing country health care providers lack computers with Internet
connections, are not adequately trained to obtain information through
the Internet, or do not have access to other medical databases.1
In addition, much published research is of poor quality,2
some is unimportant,3 and some is fraudulent.4
Identifying worthy medical research is an important but challenging
task, since many readers lack the necessary skills to analyze technical
reports.
The inability to identify sound medical research leads to continued
use of inappropriate or poor practices and failure to adopt useful
practices in a timely manner. For example, 13 years passed between
emergence of clear evidence that giving thrombolytic drugs ("clot
busters") to victims of heart attack saves lives and when the
treatment was finally recommended by at least half of cardiology texts
and review articles.5
Women's health care has long suffered many unproved, worthless, and
harmful practices based on faulty (or no) medical research evidence.
Examples in obstetrics include routine shaving of the perineum before
delivery, routine elective low forceps, routine episiotomy, routine
electronic fetal monitoring in labor, urinary estriol collection to
monitor fetal well-being, and home uterine-activity monitoring.6
Examples in family planning include requiring a blood test or Pap smear
before starting a woman on hormonal contraceptives.7
Such inappropriate medical practices can be reduced, however, if health
care providers embrace evidence-based medicine: a systematic, diligent
search for the best available evidence on a given clinical question.
After reviewing the evidence, the practitioner must use his or her
skills and unique understanding of patients and their wishes to evaluate
that evidence.8
How can health care providers find and identify research results worthy
of putting into practice?
First, they can turn to systematic reviews of the medical literature and
practice guidelines based on evidence. These include the Cochrane
Library, an international effort to identify, analyze, and
disseminate the world's randomized controlled trials in many areas of
medicine. While the Cochrane Library is available by subscription, those
Cochrane reviews related to reproductive health are available free to
researchers and health care providers in developing countries through
the Reproductive
Health Library of the World Health Organization (WHO).
Several major organizations use evidence-based medicine to generate
practice guidelines. The Canadian Task Force on the Periodic Health
Examination and the U.S. Preventive Services Task Force both develop
guidelines that rate the quality of evidence and strength of
recommendations that the evidence supports. Specialty societies, such as
the London-based Royal College of Obstetricians and Gynaecologists,
produce evidence-based, practical guidelines that also reflect the
strength of the recommendations. In addition, WHO has helped to place
family planning practice on a more secure scientific footing. WHO's
medical eligibility criteria for contraceptive use blend recent
research evidence with the judgment of experienced health care
providers. These guidelines have helped eliminate needless barriers to
safe contraception.
In summary, much research is flawed or inconsequential, and some is
fabricated. Hence, health care providers need to approach with
skepticism reports of new findings, especially those from observational
studies. Evidence-based systematic reviews of the literature and
evidence-based practice guidelines are sound, practical tools for
improving medical and public health practice around the world.
References
- Geyoushi B, Matthews Z, Stones R. Pathways to evidence-based
reproductive healthcare in developing countries. Br J Obstet
Gynaecol 2003;110(5):500-7.
- Schulz KF, Chalmers I, Grimes DA, et al. Assessing the quality of
randomization from reports of controlled trials published in
obstetrics and gynecology journals. JAMA 1994;272(2):125-28;
Vandekerckhove P, O'Donovan PA, Lilford RJ, et al. Infertility
treatment: from cookery to science. The epidemiology of randomised
controlled trials. Br J Obstet Gynaecol 1993;100(11):1005-36;
Halpern SD, Karlawish JH, Berlin JA. The continuing unethical
conduct of underpowered clinical trials. JAMA
2002;288(3):358-62.
- Abraham P. Duplicate and salami publications. J Postgrad Med
2000;46(2):67-69.
- Rossiter EJ. Reflections of a whistle-blower. Nature
1992;357(6378):434-46; Heymsfield SB, Glenn JF. Decreased myocardial
taurine levels and hypertaurinuria in a kindred with mitral-valve
prolapse and congestive cardiomyopathy. N Engl J Med
1983;308(23):1400. Retraction of: Darsee JR, Heymsfield SB.
Decreased myocardial taurine levels and hypertaurinuria in a kindred
with mitral-valve prolapse and congestive cardiomyopathy. N Engl
J Med 1981;304(3):129-35.
- Antman EM, Lau J, Kupelnick B, et al. A comparison of results of
meta-analyses of randomized control trials and recommendations of
clinical experts. Treatments for myocardial infarction. JAMA
1992;268(2):240-48.
- Enkin M, Keirse MJ, Neilson J, et al. Effective care in pregnancy
and childbirth: a synopsis. Birth 2001;28(1):41-51.
- Stewart FH, Harper CC, Ellertson CE, et al. Clinical breast and
pelvic examination requirements for hormonal contraception: current
practice vs evidence. JAMA 2001;285(17):2232-39.
- Sackett DL, Rosenberg WM, Gray JA, et al. Evidence based medicine:
what it is and what it isn't. BMJ 1996;312(7023):71-72.
Other
Evidence-Based Medical Web Resources
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Netting
the Evidence is a database of organizations, learning
resources, journals, and software related to evidence-based
medicine. Sources are divided by category, such as
"searching," "appraising," and
"implementing," and can also be searched alphabetically.
Columbia University's Health Sciences Library maintains this annotated
bibliography related to evidence-based medicine.
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Quality
of Evidence of Effectiveness
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The quality of evidence of the effectiveness of interventions
that address unresolved health issues is increasingly being
systematically reviewed and graded, yielding more specific
recommendations for various clinical practices.
Criteria established and recently updated by the U.S.
Preventive Services Task Force are widely used for this purpose.
The task force, an independent panel of experts in prevention and
primary care, rigorously evaluates clinical research to assess the
merits of preventive measures, including screening tests,
counseling, immunizations, and drug therapy to prevent disease.
Quality-of-evidence ratings below describe the relative strength
of findings from various types of study designs.
I: Evidence obtained from at least one properly
randomized controlled trial.
II-1: Evidence obtained from well-designed controlled
trials without randomization.
II-2: Evidence obtained from well-designed cohort or
case-control analytic studies, preferably from more than one
center or research group.
II-3: Evidence obtained from multiple time series with
or without the intervention. Dramatic results in uncontrolled
experiments could also be regarded as this type of evidence.
III: Opinions of respected authorities, based on
clinical experience, descriptive studies, and case reports or
reports of expert committees.
Relationships between levels of quality of evidence and
strength of recommendations, which also are graded, are discussed here.
— Kim Best
Source: Harris RP, Helfand M, Woolf SH, et al.
for the Methods Work Group, Third U.S. Preventive Services Task
Force. Current methods of the U.S. Preventive Services Task Force:
a review of the process. Am J Prev Med 2001;20(3S):21-35.
Available online.
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