Does providing evidence-based care improve outcomes for patients?
No such evidence is available from randomized trials because no investigative team or research granting agency has yet overcome the problems of sample-size, contamination, blinding, and long-term follow-up which such a trial requires. Moreover, there are ethical concerns with such a trial: is withholding access to evidence from the control clinicians ethical? On the other hand, population-based "outcomes research" has repeatedly documented that those patients who do receive evidence-based therapies have better outcomes than those who don't.
For positive examples, myocardial infarction survivors prescribed aspirin or beta-blockers have lower mortality rates than those who aren't prescribed these drugsi,ii, and where clinicians use more warfarin and stroke unit referrals, stroke mortality declines by >20%iii. For a negative example, patients undergoing carotid surgery despite failing to meet evidence-based operative criteria, when compared with operated patients who meet those criteria, are more than 3 times as likely to suffer major stroke or death in the next monthiv.
- Krumholz HM, Radford MJ, Ellerbeck EF, Hennen J, Meehan TP, Petrillo M, et al. Aspirin for secondary prevention after acute myocardial infarction in the elderly: prescribed use and outcomes. Ann Intern Med 1996;124:292-8.
- Krumholz HM, Radford MJ, Wang Y, Chen J, Heiat A, Marciniak TA. National use and effectiveness of beta-blockers for the treatment of elderly patients after acute myocardial infarction. National Cooperative Cardiovascular Project. JAMA 1998;280:623-9.
- Mitchell JB, Ballard DJ, Whisnant JP, Ammering CJ, Samsa GP, Matchar DB: What role do neurologists play in determining the costs and outcomes of stroke patients? Stroke.1996;27: 1937-43
- Wong JH, Findlay JM, Suarez-Almazor ME. Regional performance of carotid endarterectomy appropriateness, outcomes and risk factors for complications. Stroke 1997;28:891-8.