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.
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.
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.
