Simplifying the language of evidence to improve patient care

,

Applied Evidence

Simplifying the language of evidence to improve patient care

J Fam Pract. 2004 February;53(2):111-120

PDF Download

References

1. Evidence-based medicine . A new approach to teaching the practice of medicine. JAMA 1992;268:2420-2425.

2. Slawson DC, Shaughnessy AF, Bennett JH. Becoming a medical information master: feeling good about not knowing everything. J Fam Pract 1994;38:505-513.

3. Shaughnessy AF, Slawson DC, Bennett JH. Becoming an information master: a guidebook to the medical information jungle. J Fam Pract 1994;39:489-499.

4. Siwek J, Gourlay ML, Slawson DC, Shaughnessy AF. How to write an evidence-based clinical review article. Am Fam Physician 2002;65:251-258.

5. Systems to rate the strength of scientific evidence. Summary, evidence report/technology assessment: number 47. AHRQ pub. no. 02-E015, March 2002. Agency for Healthcare Research and Quality, Rockville, Md. Available at: www.ahrq.gov/clinic/epcsums/strengthsum.htm. Accessed on November 13, 2003.

6. Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow CD, Teutsch SM, et al. Current methods of the U.S. Preventive Services Task Force: a review of the process. Am J Prev Med 2001;20(3 suppl):21-35.

7. Clarke M, Oxman AD. Cochrane reviewer’s handbook 4.0. The Cochrane Collaboration, 2003. Available at: www.cochrane.org/resources/handbook/handbook.pdf. Accessed on November 13, 2003.

8. Gyorkos TW, Tannenbaum TN, Abrahamowicz M, Oxman AD, Scott EA, Millson ME, et al. An approach to the development of practice guidelines for community health interventions. Can J Public Health 1994;85(suppl 1):S8-S13.

9. Briss PA, Zaza S, Pappaioanou M, et al. Developing an evidence-based guide to community preventive services—methods. Am J Prev Med 2000;18(1 suppl):35-43.

10. Greer N, Mosser G, Logan G, Halaas GW. A practical approach to evidence grading. Jt Comm J Qual Improv 2000;26:700-712.

11. Guyatt GH, Haynes RB, Jaeschke RZ, et al. Users’ guides to the medical literature: XXV. Evidence-based medicine: principles for applying the users’ guides to patient care. JAMA 2000;284:1290-1296.

12. Major cardiovascular events in hypertensive patients randomized to doxazosin vs chlorthalidone: the antihypertensive and lipid-lowering treatment to prevent heart attack trial (ALLHAT) JAMA 2000;283:1967-1975.

13. Echt DS, Liebson PR, Mitchell LB, et al. Mortality and morbidity in patients receiving encainide, flecainide, or placebo. N Engl J Med 1991;324:781-788.

14. Lepor H, Williford WO, Barry MJ, et al. The efficacy of terazosin, finasteride, or both in benign prostatic hyperplasia. N Engl J Med 1996;335:533-539.

15. Moseley JB, O’Malley K, Petersen NJ, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002;347:81-88.

16. Dwyer T, Ponsonby AL. Sudden infant death syndrome: after the “back to sleep” campaign. BMJ 1996;313:180-181.

17. Yusuf S, Dagenais G, Pogue J, Bosch J, Sleight P. Vitamin E supplementation and cardiovascular events in high-risk patients. N Engl J Med 2000;342:154-160.

18. Moayyedi P, Soo S, Deeks J, Delaney B, Innes M, Forman D. Pharmacological interventions for non-ulcer dyspepsia. Cochrane Database Syst Rev 2003;(1):CD001960.-

19. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial. JAMA 2002;288:321-333.

20. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 1998;352:837-853.

21. Meunier PJ, Sebert JL, Reginster JY, et al. Fluoride salts are no better at preventing new vertebral fractures than calcium-vitamin D in postmenopausal osteoporosis: the FAVO Study. Osteoporos Int 1998;8:4-12.

22. MacMahon S, Collins R, Peto R, Koster RW, Yusuf S. Effects of prophylactic lidocaine in suspected acute myocardial infarction. An overview of results from the randomized, controlled trials. JAMA 1988;260:1910-1916.

23. Grumbach K. How effective is drug treatment of hypercholesterolemia? A guided tour of the major clinical trials for the primary care physician. J Am Board Fam Pract 1991;4:437-445.

24. Heidenreich PA, Lee TT, Massie BM. Effect of beta-blockade on mortality in patients with heart failure: a metaanalysis of randomized clinical trials. J Am Coll Cardiol 1997;30:27-34.

25. Centre for Evidence-Based Medicine. Levels of evidence and grades of recommendation. Available at: www.cebm.net/levels_of_evidence.asp. Accessed on November 13, 2003.

26. Family Practice Inquiries Network. (FPIN). Available at: www.fpin.org. Accessed on November 13, 2003.

FIGURE 1
Determining the strength of a recommendation based on a body of evidence

FIGURE 2
Determining the level of evidence for an individual study

The advantages of SORT

We believe there are several advantages to our proposed taxonomy. It is straightforward and comprehensive, is easily applied by authors and physicians, and explicitly addresses the issue of patient-oriented versus disease-oriented evidence. The latter attribute distinguishes SORT from most other evidence grading scales. These strengths also create some limitations. Some clinicians may be concerned that the taxonomy is not as detailed in its assessment of study designs as others, such as that of the Centre for Evidence-Based Medicine (CEBM).²⁵ However, the primary difference between the 2 taxonomies is that the CEBM version distinguishes between good and poor observational studies while the SORT version does not. We concluded that the advantages of a system that provides the physician with a clear recommendation that is strong (A), moderate (B), or weak (C) in its support of a particular intervention outweighs the theoretic benefit of distinguishing between lower quality and higher quality observational studies, particularly because there is no objective evidence that the latter distinction carries important differences in clinical recommendations.

Any publication applying SORT (or any other evidence-based taxonomy) should describe carefully the search process that preceded the assignment of a SORT rating. For example, authors could perform a comprehensive search of MEDLINE and the gray literature, a comprehensive search of MEDLINE alone, or a more focused search of MEDLINE plus secondary evidence-based sources of information.

Walkovers: Creating linkages with SORT

Some organizations, such as the CEBM,²⁵ the Cochrane Collaboration,⁷ and the US Preventive Services Task Force (USPSTF),⁶ have developed their own grading scales for the strength of recommendations based on a body of evidence and are unlikely to abandon them. Other organizations, such as FPIN,²⁶ publish their work in a variety of settings and must be able to move between taxonomies. We have developed a set of optional walkovers that suggest how authors, editors, and readers might move from 1 taxonomy to another. Walkovers for the CEBM and USPSTF taxonomies are shown in Table 4.

Many authors and experts in evidence-based medicine use the “Level of Evidence” taxonomy from the CEBM to rate the quality of individual studies.²⁵ A walkover from the 5-level CEBM scale to the simpler 3-level SORT scale for individual studies is shown in Table 5.

TABLE 4
Suggested walkovers between taxonomies for assessing the strength of a recommendation based on a body of evidence

SORT	CEBM	BMJ’s Clinical Evidence
A. Recommendation based on consistent and good-quality patient-oriented evidence	A. Consistent level 1 studies	Beneficial
B. Recommendation based on inconsistent or limited-quality patient-oriented evidence	B. Consistent level 2 or 3 studies or extrapolations from level 1 studies	Likely to be beneficial Likely to be ineffective or harmful (recommendation against)
	C. Level 4 studies or extrapola-tions from level 2 or 3 studies	Unlikely to be beneficial (recommendation against)
C. Recommendation based on consensus, usual practice, disease-oriented evidence, case series for studies of treatment or screening, and/on opinion	D. Level 5 evidence or troublingly inconsistent inconclusive studies of of any level	Unknown effectiveness
SORT, Strength of Evidence Taxonomy; CEBM, Centre for Evidence-Based Medicine; BMJ, BMJ Publishing Group.

TABLE 5
Suggested walkover between CEBM and SORT for assessing the level of evidence of an individual study

SORT	CEBM
	Treatment/screening	Other categories
Level 1	Levels 1a to 1c	Levels 1a to 1c
Level 2	Level 2 or 3	Levels 2 to 4
Level 3	Level 4 or 5 and any study that measures measures intermediate or surrogate outcomes	Level 5 andany study that intermediate or surrogate outcomes
CEBM, Centre for Evidence-Based Medicine;
SORT, Strength of Recommendation Taxonomy

SORT can improve patient care

The SORT is a comprehensive taxonomy for evaluating the strength of a recommendation based on a body of evidence and the quality of an individual study. If applied consistently by authors and editors in the family medicine literature, it has the potential to make it easier for physicians to apply the results of research in their practice through the information mastery approach and to incorporate evidence-based medicine into their patient care.

Like any such grading scale, it is a work in progress. As we learn more about biases in study design, and as the authors and readers who use the taxonomy become more sophisticated about principles of information mastery, evidence-based medicine, and critical appraisal, it is likely to evolve. We remain open to suggestions from the primary care community for refining and improving SORT.

Acknowledgments

The authors thank Lee Green, MD, MPH, John Epling, MD, Kurt Stange, MD, PhD, and Margaret Gourlay, MD, for helpful comments on the manuscript. The authors indicate that they do not have any conflicts of interest. Sources of funding: none reported. This article has been simultaneously published in print and online by American Family Physician, Journal of Family Practice, Journal of the American Board of Family Practice, and online by Family Practice Inquiries Network. Copyright © 2004 American Family Physician, a publication of the American Academy of Family Physicians. All rights reserved.