Flashcards in PA20298 evidence based medicine Deck (120)
Are chance, bias and confounding CAUSAL of a certain event?
No they are not causal.
If non of these were present, then ONE VARIABLE IS CAUSAL OF THE OTHER VARIABLE. If one or more of these factors are present, we cannot be sure if one variable causes what happens to the other variable.
What types of trials happen in drug development?
Pre clinical trials during research
Phase I,II and III clinical trials
Post marketing evaluation trials
What are randomised controlled trials (RCT) distinguishing feature?
Study subjects are RANDOMLY allocated to receive one or other of the alternative treatments under study. I.e group 1 may receive a new treatment whilst group 2 receive old treatment or a placebo.
The 2 groups of subjects are followed up in exactly the same way, the only difference between them is the care they receive.
What is the most important advantage of proper randomisation being done in randomised controlled trials?
It minimises allocation bias.
What are inclusion and exclusion criteria?
A way of establishing precision in your cohort/ case control study.
They define the population that will be included in your study.
Criteria that must be met for people to be included/ excluded in your study.
It is important to ensure that no group of people is included or excluded for a non scientific reason.
They effect the extent to which the results of a study can be generalised to the whole population.
What is inclusion criteria?
The criteria for including a patient in the study. What characteristics must a patient have to be included in the study?
What happens if inclusion criteria is too narrow?
if the criteria are too narrow, subject recruitment may be difficult
What happens if the inclusion criteria are too broad?
if the criteria are too broad this may reduce the level of control in the study design, as it increases the chance that the groups may differ/be effected by some other variable.
If the groups differ in any way other than the treatment, a confound has been Introduced, that could lead to incorrect conclusions..
What do Randomised control trials need to consider?
Carefully selected and specified indications (valid reasons to use a certain treatment)
Consider use of a homogeneous population (consider inclusion and exclusion criteria)
Short term therapy- cant have people coming back for checkups 20 years later, want a quick answer.
Can use randomised controlled trials to detect side effects of a treatment.
What is pharmacoepidemiology?
The principles of chronic disease epidemiology applied to the area of clinical pharmacology.
What happens with non-experimental/ observational studies?
an observational study draws conclusions on the possible effect of a treatment on subjects, where the assignment of subjects into treated and non treated control groups is outside often control of the investigator. These are NOT EXPERIMENTS!
There is no control over exposures assigned so the only source of discretion is the selection of the subjects.
Confounding will occur, as less control over the population picked for the study.
No risk to patients
What are cohort studies?
This study identifies a group of people and follows them over a period of time to see how their exposures effect their outcomes. Cohort studies are normally used to look at the effects of suspected risk factors that cannot be controlled experimentally, for example the effect of smoking on lung cancer.
It is a type of observational study.
A cohort is a group of people who share a COMMON CHARACTERISTIC. The comparison group may be e rest of the population or a group who have not been exposed to the treatment, I.e the control group.
Advantages and disadvantages of cohort studies?
Efficient for rare exposures
Multiple effects can be studied
Less prone to bias
Can calculate incidence rate, relative risks, and absolute risks
Can have difficulties with loss of follow up
May have problems with BIAS
What are case control studies?
An epidemiology study
Often used to identify risk factors for a medical condition
Compares a group of patients who have the condition with a group of patients who don't, and looks back in time to see how the characteristics of the two groups differ.
Case control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have the condition/ disease with patients that don't but are otherwise similar (the controls)
In case control studies, what do the case subjects have? What do the control subjects have?
Cases- have disease of interest
Controls- are free from the disease of interest
You're comparing the differences before treatment, in risk factors, protective factors, etiologic agent (causal agent/microorganism)
Advantages of case control studies?
Evaluation of rare diseases.
Diseases with long latent (inactive) periods
Relatively quick to conduct
Allows study of multiple exposures (to a drug/ treatment)
No risks to subjects
Useful in early stages when identifying potential risk factors of disease.
Disadvantages of case control studies?
Inefficient for rare exposures
Difficult to choose an appropriate control group
Prone to BIAS
What is bias in studies?
The introduction of systematic error in the study. This may be at the point of study design. It cannot be eliminated at the point of analysis.
Bias may be in terms of;
Selection of study subjects
Exposure (treatment) classification for each patient
Bias can result in over or underestimated risks
Why are randomised controlled trials randomised?
To eliminate confounding (outcome effected due to some other variable)
Examples of some confounding factors?
Newer drugs given to iller people, therefore they may appear to have more side effects when it's really just effects of having the illness
Smokers are more likely to have adverse health outcomes,so the medications they're taking are more likely to have advers side effects
Older people may be more likely to have more side effects
Confounding is a result of certain characteristics in the study population.
It can be dealt with through;
Randomisation of exposure
Confounding is the distortion of a risk estimate due to the mixture of the people in the study population.
A confounder is a risk factor for the disease and is correlated with the exposure independent of disease.
What must pharmacists consider when conducting a clinical check?
How treatment will be administered and monitored
What does clinical pharmacy generally describe?
Knowledge, skills and attitudes required by a pharmacist to contribute to patient care.
Pharmacists provide care that optimises medication therapy and promotes health, wellness and disease prevention.
Blends a caring orientation with specialised therapeutic knowledge, experience and judgment to ensure optimal patient outcomes.
What has pharmaceutical care been defined as?
The responsible provision of drug therapy for the purpose of achieving definite outcomes that improve a patients quality of life
What do clinical pharmacist do before the prescription?
Prescribing advice to doctors
Develop prescribing guidelines and tools
Medicines reconcilliation/ history taking
What do clinical pharmacists do during the prescription?
Clinical check of the prescription
Counselling the patient
What do clinical pharmacists do after the prescription?
Monitor the effectiveness (drug and disease)
Monitor adverse effects (side effects)
Ongoing patient counselling
Medicines usage review
Why do we need clinical pharmacists?
To improve patient care and increase effectiveness
Reduce adverse drug events such as prescribing errors, interactions, side effects
What do the patient factors consist of in a clinical check?
Age and sex
Allergies and intolerances