EBP Flashcards
the 5 steps of EBP
Ask an answerable question
Access/acquire information
Appraise the articles found
Apply the information in your clinical practice
Audit the process you have undertaken
define EBP
evidence based practice is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients
PICO stands for
Patient, problem, population or person
Intervention, diagnostic test or prognostic factor/issue
Comparison
Outcome(s)
4 elements of EBP
- Clinical expertise - experience or knowledge
- Research evidence
- Practice context - funding limitations and availability
- Patient values and circumstances
Explain why EBP is important.
- It aims to provide effective cares to improve healthcare outcomes.
- To meet the societal expectation from patients that the clinical practise is based on accurate medical information, and that the care is most effective at the time.
- Promotes an attitude of maintaining professional accountability
- Ensures health resources are used wisely and are informed by the high-quality evidence.
Describe the scope of EBP healthcare
- Permeates all of healthcare and beyond
- It has a significant impact on more than just the clinical domain, affecting health policies and major health systems
- It can be universally applied across disciplines and across sectors
- Used in areas such as policy formation and implementation, purchasing and management
Explain the ‘Ask’ step of the five steps that make up the EBP process
Convert your information needs into an answerable clinical question.
Explain the ‘Acquire / Access’ step of the five steps that make up the EBP process
Develop a systematic search strategy to find the best evidence to answer the clinical question.
Explain the ‘Critically appraise the evidence’ step of the five steps that make up the EBP process
critically evaluate the evidence for its validity, impact and methodology.
Explain the ‘Apply the information’ step of the five steps that make up the EBP process
After deciding that the evidence is of an appropriate quality, integrate the evidence with clinical expertise, the patient’s values, patients’ value and circumstances, and information from the practice
Explain the ‘Audit’ step of the five steps that make up the EBP process
Evaluate the effectiveness and weakness of practising steps 1-4, think about ways to improve for next time.
What is the power of study?
The probability that the study will find a true effect (relationships) between variables.
The higher the power, the less likely to have type 2 errors, which is wrongly accepting null hypothesis, leading to false negative results.
Increasing the sample size increases power
If a test has a high sensitivity…
it means the test is sensitive to give positive result, and therefore, it is less likely to give false negative. Thus, if the result is negative, you rule the condition out.
If a test has a low sensitivity…
It means the test is too caution in giving positive result, and the chance of false negative can be high.
if a test has high specificity…
It means the test is with lower chance of false positive. Thus, a positive result rules the condition in.
Define research fraud.
An act of deception or misrepresentation of one’s own work which violates the scientific value, the ethical standards, or the Law.
It can take the form of plagiarism, falsification of data, and irresponsible authorship.
‘just-in-case’
Push information
Information that is made available when it is generated, or when people believe that health professionals should know about it, regardless of whether they need it or not.
What is the placebo effect?
participants feeling improvement when they believe the intervention is effective, even though it is a fake treatment.
Blinding is a key to ensure the validity.
What is the Hawthorne effect?
The Hawthorne effect is a phenomenon where people change their behavior or performance when they know they are being observed or studied.
Difference between statistical significance and clinical significance.
Statistical significance is a measure of how likely a result is due to chance or random variation. It is usually expressed as a p-value, which is the probability of obtaining a result as extreme or more extreme than the observed one, assuming that the null hypothesis (no effect or no difference) is true.
Clinical significance is a measure of how meaningful a result is for the decision making.
What is absolute risk?
is the probability or chance of an event happening, such as developing a disease or experiencing a side effect.
It is usually calculated by dividing the number of events that occurred in a group by the number of people in that group.
What is absolute risk reduction?
The difference in the absolute risk between the control group and the treated group
What is a negative predictive value?
Probability of NOT having a disease when the test result is negative
Closer to 100% the better a test is at ruling OUT a disease
What is a positive predictive value?
Probability of disease in a patient with a positive (abnormal) test result
Closer to 100% the better a test is at ruling IN a disease
What is sensitivity?
Sensitivity is the probability of people WITH Disease X should have a POSITIVE test. (100%: not necessarily true positive, but if a person has disease, must be positive)
Indicates how well a test can identify positive (sensitive in detecting positive). Thus, the false negative ratio is low.
What is specificity?
Specificity is the probability of people without a disease that have negative results.
Indicates how well a test can identify negatives.
A test with high specificity will have a low ratio of false positives.
What is Type I error?
Also known as false positive, occur when you see things that are not there. Can be denoted by alpha (the probability that you will reject the null hypothesis when it is true).
What is Type II error?
Also known as false negative, occurs when you do not see thing that are there. Denoted by beta (the probability that you will accept null hypothesis when it is false).
Association
A statistical relationship between two or more things (event, condition, characteristics or other variable).
causation
Something (an event, condition, characteristic or combination of these) that plays an essential role in producing an effect.
What is a reference or gold standard test?
This is the diagnostic test or tests that we believe provides the most accurate method for identifying patients with or without a particular condition
“Just-in-time” information
Pull information
Information that is made available when it is needed, or when someone has a specific question or problem to solve, rather than being provided in advance (just in case).
types of clinical questions
- intervention
- diagnostic
- prognostic
- patient’s experiences and concerns
observational study
researchers OBSERVE what is occurring only. They DO NOT intervene
experimental study
researchers both CONTROL / INTERVENE in the study AND OBSERVE what happens.
what study designs are analytical studies
- randomised controlled
- cohort
- case control
- cross-sectional
what study designs are descriptive studies
- cross-sectional
- ecological
- case studies
what study designs are experimental studies
- cohort
- case control
- cross-sectional
- ecological
- case studies
list the study designs from highest to lowest quality of evidence
systemic reviews, cohort studies, RCTs, critically appraised evidence (evidence syntheses), background information/expert opinion, case controlled studies, critically appraised individual articles (article synopses)
- systemic reviews
- critically appraised evidence (evidence syntheses)
- critically appraised individual articles (article synopses)
- RCTs
- cohort studies
- case controlled studies
- background information/expert opinion
case report studies
detailed description of a patient/presentation that is unusual for some reason
rare disease or unusual presentation of common disease
case series studies
a report that combines multiple cases
may potentially include hypothesis
How do we know it is a case series studies?
- discusses multiple patients
- its descriptive (describes the patients)
- no comparison groups
cross-sectional study
- can be both analytic and descriptive
- single point in time
- obtain exposure and outcome at the same time
ecological studies
compares levels of exposure and or disease across population not individual
cohort studies
- follows a group of people overtime who have been exposed to a possible risk factor and a group who have been not
- can be prospective or retrospective
always start with the exposure status of the participant, then look for the outcome of interest. For example: smoker or non-smoker.
case control studies
- compares a group of people who have the outcome of interest (cases) with a group who do not (control)
always start with the outcome status of the participant, then look for the exposure(s) of interest. For example: cancer or no cancer
randomised control studies
- special type of cohort study
- examines cause-effect relationship between predictor and outcome variables
- at least two groups (experimental and control/comparison)
- minimises confounding
- randomisation
2 types of variables
numerical and categorical
numerical variable can be split into
continuous and discrete (whole numbers)
categorical variables can be split into
nominal (eg. yes or no) and ordinal (eg. low, normal, high)
standard deviation
- variation in the data around the mean
- is a measure of precision
- larger the number, the more variation in the data
null hypothesis
the outcome of patients taking dug A will be no different to those patients taking drug B
alternative hypothesis
if it was found that there was a statistically significant difference between drug A and drug B outcomes (drug A was more effective than drug B)
reject the null hypothesis and accept the alternative hypothesis
p-value
provides us with information on the PROBABILITY that the difference we find is due to chance alone
type I error
false positive - mistakenly rejecting the null hypothesis
reject the null hypothesis is when it is actually true
type II error
false negative - mistakenly accept the null hypothesis
accept the null hypothesis when it is actually false
confidence intervals when following a difference between two groups
if the interval includes 0, it is considered not statistically significant
confidence interval when following a ratio
if the interval includes 1, it is considered not statistically significant
risk + formula
number of times an event is likely to occur divided by the total number of events possible
- same meaning as a probability
odds + formula
number of times an event is likely to occur divided by the number of times it is likely not to occur
- another way of expressing chance
experimental event rate + formula
number of experimental arm participants with the outcome of interest / the total number of participants in the experimental arm
control event rate + formula
number of control arm participants with the outcome of interest / total number of participants in the control arm
relative risk + formula
compares the amount of disease/outcome/event in one group relative to that in another
RR = experimental event rate /control event rate
how to interpret relative risk
RR = 1 –> no difference between groups
RR > 1 –> increased of outcome in experimental group
RR < 1 –> reduced risk of outcome in the experimental group
relative risk reduction
proportional reduction in an event of interest
- 0 is the no effect value
absolute risk reduction + formula
the absolute drop in risk going from the control to the experimental group
ARR = control event rate - experimental event rate
odds ratio + formula
- alternative way of comparing how likely outcomes are between two groups
the odds of having the outcome in the experimental group / the odds of having outcome in the control group
how to interpret odds ratio
OR = 1 –> same outcome rates in both groups (no effect)
OR > 1 –> likelihood of developing the outcome in the experimental group is greater
OR < 1 –> likelihood of developing the outcome in experimental arm is less
clinical significance
judges whether the differences are worthwhile in real time
number needed to treat (NNT)
- number of patients who must be treated with the intervention, compared to the control, for one to benefit
- is a whole number
- should be rounded up
number needed to harm (NNH)
- the number of patients treated for one to have an adverse outcome, compared with the control intervention
- is a whole number
- should be rounded down
internal validity
to extent to which the results of a study reflect the ‘true situation’ in the study sample
external validity
generalisability of the results of a study
selection bias + common sources
- there is a systemic difference between people included in the study and those who are not
- when study and comparison groups are selected inappropriately
- volunteers
- low response rates
- ascertainment or detection bias
- healthy worker effect
- loss to follow up
measurement bias
- error in the information we collect about people
- error could be random or systemic
confounding
A mixing or muddling of effects that can occur when the relationship we are interested in is confused by the effects of something else.
association
A statistical relationship between two or more things (event, condition, characteristics or other variable)
causation
Something (an event, condition, characteristic or combination of these) that plays an essential role in producing an effect
define reference standard or gold standard
This is the diagnostic test or tests that we believe provides the most accurate method for identifying people with a particular condition or not
define index test
This is the diagnostic test being investigated
SpPin
when a highly SPecific test is used, a Positive test result tends to rule IN the disorder
SnNout
when a highly SeNsitivity test is used, a Negative test result tends to rule OUT the disorder
likelihood ratio
- alternative way of describing performance of a diagnostic test
- more useful than predictive values
- results are not influences by prevalence
interpreting likelihood ratios
positive likelihood ratio of > 2 helps rule in a disease
positive likelihood ratio of > 10 is an extremely good test for ruling in disease
negative likelihood ratio of < 0.5 helps rule out disease
negative likelihood ratio of < 0.1 s an extremely good test for ruling out disease
what are the PICO components in a qualitative question
P = population
I = refers to ‘interest’ or ‘issue’
C = generally not used
O = instead of the outcome, you may wish to consider what is being ‘evaluated’
what is qualitative research
Research providing detailed narrative descriptions and explanations of phenomena investigated, with lesser emphasis given to numerical quantifications
deductive research
Top down – start with the conclusion and then tell us how you arrived there.
general to specific
inductive research
Bottom up
specific to general
why use guidelines
- help address information overload
- reduce variations in practice
- improve patient outcomes
pros of clinical guidelines
- achieves better health outcomes
- improves decisions about health care
- saves time
- provides an overview of the prevention, diagnosis and management of the condition
cons of clinical guidelines
- not easy to develop —> requires a lot of time, money, expertise and effort
- lengthy process
- evidence used may not be the most current by the time it is published
- “living guidelines” is how they deal with this problem where they continuously update
- does not provide clear information about conflicts of interest within the development or how these were handled during the process
- duplication and overlap of guidelines —> for clinical conditions there can be multiple guidelines produced by different developers which can make it confusing for the people
- little to no shared decision making —> does not provide the benefits and the harms of the options
- does not incorporate tools such as decision aids
- deal with single conditions in isolations —> patients present with a range of comorbid conditions and can exclude these people
quality of evidence - GRADE
indicates the extent to which one can be confident that an estimate of effect is adequate to support a particular recommendation
strength of a recommendation - GRADE
indicates the extent to which one can be confident that adherence to the recommendation will do more good than harm
the quality of evidence grading used by GRADE
- high
- moderate
- low
- very low
the two levels of recommendation strength within the GRADE system
strong and weak
order the 6S pyramid from top to bottom
- systems
- summaries
- synopses of syntheses
- syntheses
- synopses of studies
- studies
What are the different types of quantitative research?
Analytic - identifies CAUSES of disease and EVALUATES interventions i.e. compare those with or without disease OR with and without exposure. Focussed on WHY
Descriptive- describing person, place or time using who, what, where and when. No WHY i.e. describe a disease in single person or national health survey
What are the different types of ANALYTIC quantitative research?
Observational - no controlling, influencing or intervening but only observing i.e. skill in a radiographic exam
Experimental - researchers intervening with the participants life against normal course of life then measuring outcome i.e. drug given for a stud
