Clinical Trials Flashcards
What is the order of clinical trial quality
MEta analysis Systematic Review Practie Guideline Ransomised controlled trial Cohort strudy case control study case report
what is a case report?
Article that describes and interprets an individual case, often written in the form of a detailed story: - unique cases
Cases that show variation in a disease or condition
Cases that show may yield new or useful information
what are the advantages of a case report?
¬ First line of evidence
¬ Cheap
¬ Educational
¬ Easy to take observations
¬ Good way of HCP communicating (SBAR report)
¬ Pharmacovigilance
¬ Can help with identification of new trends or diseases
¬ Help detect new drug s/e and potential uses
Identifies rare manifestations of a disease
what are the disadvantages of a case report
¬ Cannot make a conclusion, only an observation
¬ Cannot establish a cause and effect relationship (as only a small number of cases)
¬ Lowest level of evidence
¬ Cases may not be generalised
¬ Not cased on systematic stidies
¬ Causes or associations detailed may have other explaations, danger of misinterpretation
Journals may be biased
what is a case controlled study
Compares patient cases that have had the disease with controls (patients that don’t have the disease). Compare how frequently the exposure to a risk factor is present in each patient group to determine the relationship between risk factor and the disease .
Used to estimate odds
what are the advantages of a case controlled study?
¬ Quick
¬ Cheap
¬ Easy to form
¬ Suitable for studying risk factors associated with rare diseases
¬ Good to do a wee study before a big one
¬ Simultanrously look at many risk factors
Answer questions that you may not be able to answer through other study designs
what are the disadvantages of a case controlled study?
¬ Prone to bias
¬ Recall bias on past behavours
¬ Rely on emory
¬ Subjective
¬ Not efficient to form cause and analysis
¬ Can be difficult to find suitable control group
¬ Control group may be over selected
¬ Results are determined by recall (memory of person)
May be flaw in relationships between disease and risk factors (confounding influence)
what is a cohort study?
Follow cohorts and status evaluations are made with regard to disease or outcome to determine which of the initial risk factors the participant was exposed to are related to the disease (risk factors)
As the study is conducted outcome from participants in each cohort is measured and relationships with specific characteristics is determined
Difference between cohorts already exists (e.g. man/woman) the difference isn’t imposed upon them like in a clinical trial)
what are the advantages of a cohort study?
¬ Examine multiple events associated with exposure
¬ Subjects in cohorts can be matched (to limit the influence of confounding variatbles)
¬ Standardisation of criteria outcome is possible
Easier and cheaper than randomised controlled trials
what are the disadvantages of a cohort study?
¬ Expensive
¬ Time cosuming
¬ Not good for rare cases or cases that take a long time to develop
¬ Selection bias (can manipulate individuals in cohorts to achieve a specific outcome)
¬ Cohorts can be difficulat to identify due to confounding variables
¬ No randomisation so imbalances in patient characteristics could exist
¬ Blinding/masking is difficult
¬ Outcome of interest could take time to occur
Look for secondary characteristics of the participants that could influence disease being studied for (e.t. people that drink linked to lung cancer but the people that drink also smoke)
what is a randomised controlled trial
Study design that randomly assigns participants into experimental group or a control group.
One group has a medicine and the other has a placebo
As the study is conducted the only expected difference between the control and experimental group in a randomised controlled trial (RCT) is the outcome variable being studied
what are the advantages of a randomised controlled trial?
¬ No bias
¬ Easy to “blind” if you use a placebo
¬ Analused with well known statistical tools
¬ Good randomisation without any population bias
¬ Easier to make blind than observational studies
Populations of participating individuals are clearly identified
what are the disadvantages of a randomised controlled trial?
¬ Expensive and time cosuming
¬ Can be volunteer bias (population that participates may not be representative of the population as a whole)
¬ Can be subject to personal and political pressure
¬ Personal and political influences
¬ Confounding variables
¬ RCT should be a study of one population only
¬ Population that is involved shouldn’t know that the medicine they are taking is or what it is for
¬ Is the randomisation actually random
Baseline characteristics should be taken first
what is practice guidelines
A statement produced by a panel of experts that outlines current best practive to inform healthcare professionals in making clinical decisions .
Produced after a extensive systematic literature review
what are the advantages of practice guidelines
¬ Summarise best evidence ¬ Prevention ¬ Diagnosis ¬ Prognosis ¬ Therapy ¬ Harm ¬ Cost effectiveness
¬ Provides standardised guidelines for practitioners to use
¬ Statement produced after review of lots of evidence
¬ Summarise the best evidence
¬ Identify where information is intergraded into practice
¬ Created by panel of experts
¬ Evidenced based resource
¬ Taken from good quality evidence (RCT, systematic analysis, meta analysis)
