Flashcards in Chapter 3 - Types of Studies Deck (50)
Are case control studies prospective, retrospective or both?
About how many people show a placebo effect?
Why are anecdotes the weakest kind of evidence?
Some described effects could be due to anything, not necessarily a particular treatment. There are no controls. Most medical conditions get better anyway by themselves. Bias or expectation can influence reporting.
Personal communications, the weakest type of evidence.
Types of bias that can be found in clinical trials
Failed trials aren't published, trial details left out of publication, invalid comparisons can be made, effects can be misrepresented, and side-effects can be minimized.
study of disease within populations
When positive results are more likely to be published than negative ones.
Report on one patient's symptoms, signs, diagnosis, treatment, and follow-up. Usually describes a novel or unusual occurrence.
What factors associated with expectation can affect the placebo response?
Enthusiasm of the practitioner, larger pills, capsules (vs pills), injections (vs pills), colour, believing in the treatment.
Limitations of case studies
No control, sample size of only 1.
Limits of observational studies
The weakest of the scientific studies. Subjects not randomized into different groups. Show correlation at best.
Placebo pain relief is in part due to...
Opiate-receptors, and the release of dopamine.
How many papers in CAM journals report negative results?
looks into the future
What can be learned from post-marketing surveillance?
What the rare adverse effects and long-term adverse effects are.
Unique problems of testing CAMs.
Unethical to test a treatment against one already shown to work. Difficult to blind. Treatments may be patient specific.
Is it ethical for a doctor to use a placebo to diagnose if a patient's symptoms are real?
No, and it's misguided.
What is the placebo effect important?
it may be the real cause of a positive result from some studies (especially those with poor controls).
What features should interventional studies have?
Placebo controlled, randomized and double-blinded.
Gold standard treatment
most commonly used treatments
The perceived or actual improvement of a medical condition after receiving a sham intervention.
A negative placebo reaction.
3 categories of scientific medical studies
1. observational studies. 2. interventional studies. 3. summaries of other studies.
Phase III clinical trials
300-3000 participants. Randomized. Compares treatment to existing 'gold standard' treatment.
Phase II clinical trials
20-300 patients who are targets of the drug. Determines how well the drug works. Continues safety assessment.
Follows a group of subjects with a similar exposure and examines the outcome.
Perks of case control studies
Fast an inexpensive.
The most powerful type of evidence
Meta-analysis and systematic reviews.
Safety issues with CAM
Sometimes they're really dangerous. Wasting time in treating a serious condition. May interact negatively with conventional treatments. 1/2 of patients do not tell their doctors they use CAM. Waste of money.