Gulf War Veterans Treating Symptoms and Syndromes (2001) / Chapter Skim
Currently Skimming:
3. Determining Treatment Effectiveness
3. Determining Treatment Effectiveness
Pages 31-42
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 31... ...
Small pilot studies, larger controlled trials, and, finally, studies of efficacy in large clinical populations gradually build a case for the value of a given treatment. There is no point along this sequence when a treatment is unequivocally "proven" efficacious, since no single study is totally free of all methodological flaws and even a set of studies may be flawed and produce misleading conclusions.
|
From page 32... ...
Basic laboratory studies or other kinds of knowledge that do not involve direct tests of a treatment in live human patients may suggest that a treatment or class of treatments should work. No matter how compelling the arguments for plausibility, though, plausibility per se is not evidence for treatment efficacy.
|
From page 33... ...
. The most powerful evidence of treatment efficacy comes from the cumulative, consistent results of several RCTs, preferably in different patient populations and in different settings, and with extensive follow-up periods.
|
From page 34... ...
Because this design leaves open many competing explanations, it is less powerful than an RCT for assessing treatment effectiveness and is usually followed by an RCT to confirm findings. Still weaker evidence for treatment effectiveness comes from uncontrolled clinical observations or anecdotes.
|
From page 35... ...
. If we adhere to this terminology, we will find that there is very little formal evidence of treatment effectiveness for most treatments for medical problems in Gulf War veterans because relatively few true effectiveness studies have been done on any medical condition.
|
From page 36... ...
The committee is not aware of any ongoing outcomes management or outcomes research projects involving either a specific cohort of Gulf War veterans or a specific clinical condition of particular concern to Gulf War veterans. There clearly is an opportunity, though, in both VA and DoD settings to organize such a project since some of the functions of identifying a cohort of patients and gathering baseline data have already been completed through their registry programs.
|
From page 37... ...
In a meta-analysis the results of multiple studies are combined to yield an overall cross-study estimate of treatment effectiveness (DerSimonian and Laird 1986~. The key characteristics of a meta-analysis include: · explicit criteria for deciding which studies are relevant and are to be included; · explicit criteria for reviewing published or unpublished literature and choosing candidate studies for the analysis; · explicit criteria for grading studies according to rigor of design and execution and resulting strength of evidence; · explicit criteria for assigning "weights" to individual studies that reflect the strength of evidence in each one; and · a statistical method for aggregating the results of different studies that may have widely varying sample sizes, definitions of study endpoints, follow-up intervals, and statistical tests of effect.
|
From page 38... ...
Treatment effectiveness studies, including the largest and most comprehensive outcomes studies, emphasize external validity at the expense of internal validity. They may involve very large samples that are fully representative of the patients seen in routine clinical practice but may include confounding factors that weaken the inferences about cause-andeffect relationships.
|
From page 39... ...
We do, however, add outcomes/effectiveness studies to those study designs capable of providing the highest levels of evidence when the major question is one of effectiveness rather than efficacy. The above hierarchy also implies that, when the focus of evaluation is on treatment effectiveness, and in the absence of RCTs specifically designed to assess effectiveness in real-world settings, evidence from well-designed outcomes studies may provide Level I or Level II evidence and serve as the basis for clinical policies and treatment guidelines.
|
From page 40... ...
For Gulf War veterans, the situation is more complicated. Although several studies have identified specific symptoms or possibly clusters of symptoms that occur with greater frequency in Gulf War veterans, there
|
From page 41... ...
RECOMMENDATIONS The preceding discussion and analysis describes approaches used for assessing treatment effectiveness. Based on this analysis, to implement well-designed and valuable treatment effectiveness studies, the committee recommends that the VA: · use a hierarchy of evidence structure that includes effectiveness studies as well as efficacy studies for any future treatment guidelines it develops for symptoms or illnesses of Gulf War veterans;
|
From page 42... ...
Despite the fact that treatment effectiveness studies have not been conducted for the population of Gulf War veterans, there are approaches to treatment that have been shown to be beneficial across diagnostic categories. The following chapter explores a patient-centered approach to care that can be used with all patients, regardless of diagnosis, but which may prove especially beneficial to those who are experiencing symptoms but have no identifiable diagnosis.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.