| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Guest Access | Sign In via User Name/Password
|
|
|
|||||||
Guest Access | Sign In via User Name/Password |
|||||||||
Dr. Marik is Director of the Medical ICU, Washington Hospital Center; Dr. Varon is Assistant Professor of Medicine, Baylor College of Medicine, and Research Director, Department of Emergency Services, The Methodist Hospital.
Correspondence to: Joseph Varon, MD, FCCP, Department of Emergency Services, The Methodist Hospital, 6565 Fannin M 196, Houston, TX 77030; e-mail: jvaron@bcm.tmc.edu
The practice of modern medicine is based on our expanded understanding of human physiology and the pathophysiologic basis of disease together with targeted therapeutic modalities that interrupt these pathophysiologic processes. However, it is insufficient to demonstrate that an intervention alters the disease process without demonstrating an improvement in patient outcome. The randomized clinical trial (RCT) has, therefore, become the reference in medicine by which to judge the effect of an intervention on patient outcome, because it provides the greatest justification for conclusion of casualty, it is subject to the least bias, and it provides the most valid data on which to base all measures of the benefits and risk of particular therapies. Numerous ineffective and harmful therapies have been abandoned as a consequence of RCT studies, while other therapies have become integral to the care of patients and have become regarded as the "standard of care."
Although over 250,000 RCT studies have been performed, many are inconclusive or provide conflicting results.1 In this situation, the clinical question is best answered by large-scale, multicenter, high-quality RCT studies that enroll thousands of patients (megatrials).2 However, evidence from megatrials will continue to be unavailable for most medical interventions; in these situations, systematic reviews that are based on the meta-analysis of published (and unpublished) RCT studies are clearly the best strategy for appraising the available evidence. While meta-analyses have many limitations, they provide the best means of determining the significance of the treatment effect from inconclusive or conflicting RCT studies.3 4 5 Furthermore, as a result of publication bias, studies having positive results are more likely to be published in the more prestigious journals than are studies having negative results.4 6 A clinician may base his/her therapeutic approach on these select RCT studies, a decision that may lead to inappropriate patient care. It is therefore important that common medical interventions be systematically reviewed and the strength of the evidence (either positive or negative) be evaluated. Such evidence then forms the basis for establishing the standard of care, it provides the basis for performing additional studies, or it leads to the abandonment of other interventions.
The review by Rodrigo and Rodrigo in this issue of CHEST (see page 285) provides an excellent example of this process. Based on the results of a few selected studies, it is widely assumed that IV corticosteroids acutely improve lung function and reduce admission of patients admitted to the emergency department with acute asthma. Based on this impression, corticosteroids have become the standard of care in the emergency department management of these patients. The study by Rodrigo and Rodrigo clearly questions this practice. Their meta-analysis should, however, be interpreted with caution due to the small sample size of most of the trials included in their study.4
How do we grade the results of their meta-analysis and make clinical recommendations? Although a number of grading systems have been reported, we believe that many lack clinical applicability.7 8 For this reason, we suggest a modification of the existing grading systems. The elements of this grading system together with examples are listed in Table 1 , and the clinical applicability is discussed below. It should be emphasized that a single intervention may have differing grades of benefit (or harm) depending on the characteristic of the target population.
|
Meta-analysis like that performed by Rodrigo and Rodrigo is important in resolving clinical dilemmas. Health-care providers need to be "re-educated" on the scientific validity of clinical practices that are beneficial or are unproven or potentially harmful. It is interesting to note that individuals outside of medicine assume that all medical practice is based on firm scientific grounds. In the case of acute exacerbations of asthma, many patients may "request" pulse-dose corticosteroids when they present to the emergency department with dyspnea. The educational and grading process of scientific evidence in medicine has to change to a point that even our patients recognize the practice of medicine as a true science.
References
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
