PA Evidence Based Medicine Exam 1

what is evidence based medicine

a process of life-long, self-directed learning in which caring for patients creates the need for clinically important information about diagnosis, prognosis, therapy, and other clinical and health issues

a systemic approach to clinical solving which allows the integrations of the best available research evidence with clinical expertise and patient values

father of EBM

Dr. David Sackett

Dr. David Sackett

developed specific methodologies to determine the best evidence

Dr. David Sackett definition of EBM

the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of the individual patient

it means integrating individual clinical expertise with the best available external clinical evidence from systemic research

other names for EBM

EB practice

EB health practice

EB decision making

patient centered care

principles of EBM

is there evidence

location of evidence

type of study

evidence

quality, validity, and relevance

location of evidence

medical database -yes

google or social media - no

type of study

meta-analysis, randomized controlled trials, narratives, reviews, opinions, peer reviewed

in addition to evidence you must also consider

risks versus benefits

patient values, beliefs, preferences

economics/resources in the community

why learn the process of EBM

graduate as a clinician not a researcher

we must be aware of what our patients are hearing and seeing

medicine is constantly evolving

being a clinician not a researcher

prepare yourself to be an informed consumer of research

being aware of what our patients are hearing and seeing

explosion of advertising of pharmaceuticals, insurance, investments, flyers, emails, texts, phone calls, TV, social media

medicine is constantly evolving

avoid the same practice if it is no longer effective or if a better option is available

EBM is

a skill to find evidence, which requires practice

a self directed learning process

a method of asking and answering questions by finding current/existing evidence

its application of that knowledge to the care of your particular patient of interest

three main parts of EBM

utilizing evidence, patient’s values, and clinical expertise to best answer the question

how do we answer our question

by critically appraising the evidence found

5 steps in answering a question

ask

acquire

appraise

apply

assess

ask

a clinical question is a focused question that relates to a specific clinical scenario regarding patient care is used to guide clinical decision making

is essential for conduction an effective literature search and finding the most relevant evidence

two qualities of clinical questions

directly relevant to patients’ problem

phrased in ways that direct your search to relevant and precise, specific answers

types of clinical questions

therapy/intervention

diagnosis

prognosis

etiology/harm

therapy/intervention

focuses on effectiveness of treatment or prevention of a disease

diagnosis

concerns the ability of a test to accurately identify a disease or condition

prognosis

examines the course of disease over time

etiology/harm

investigates the causes of a disease or the harms of an intervention

what four elements makes up a clinical question

PICO
population

intervention

comparison

outcome

Pico

population/patient

who is the specific patient/population

gender, race, age, disease, and co-morbidities

pIco

intervention/exposure

what is the main intervention or exposure

ex. lead in water, prescribe a med, order a test, perform a procedure

piCo

comparison/control

the traditional method or standard or placebo/lack of exposure

picO

outcomes

what was accomplished/ achieved/ discovered

primary outcome

considered main objective to that study

secondary outcomes

not the primary finding, but no less important

type of questions to ask

therapy/treatment

prevention

diagnosis

prognosis

etiology

types of study

randomized controlled trial

cohort study

pain control series

prospective study

therapy/treatment

questions about the effectiveness of interventions in improving outcomes in patients

comparing two treatments

randomized controlled trials

diagnosis

questions about the ability of a test or procedure to differentiate between hose with and without a condition or disease

inquire about the accuracy of a new diagnostic test

randomized controlled trial or cohort study

prognosis

questions about the likely outcome of a condition

outcomes for patients

cohort study or case-control series

etiology/harm

questions about the causes and risks associated with a condition or treatment

cohort study

step two in the EBM process

acquire evidence

hierarchy of evidence

worst

animal/lab studies

case series and case reports

case control studies

cohort studies

randomized controlled trials

systematic reviews

meta-analysis

best

step 3 in then EBM process

appraise it

original research

is it relevant to what you are wanting to know

does it match your PICO

is it feasible to implement, perform, incorporate

does it help

does it hurt

critical appraisal process

check the validity of a study

check the reliability of the studys results

assess applicability

validity

whether the results of the study were obtained via sound scientific methods

bias may compromise the validity of the finding

reliability

determined by the effect size and how precisely that effect was estimated

examine the numerical data reported in the results section of a study

applicability

appraising the usefulness of a study for clinical decision making

to evaluate the study’s patients in comparison with the patients to whom the evidence would be applied

high quality journals and publications include

manuscripts reviewed by a group of experts in the same field but not colleagues (peer reviewed)

more than one reviewer

reviewers and authors names are blinded during the process

what is peer reviewed

it is superior

should be labeled

prevents the publication of flawed medical research

assesses the quality of the manuscript

eliminates flaws

goals in acquiring research

finding more than one article to support your CQ is best

using real original research is best

using legit sources is the best

using difference sources is the best

using different authors is the best

validity of a research article refers to

how well the results represent true findings among similar individuals outside of the study

how rigorous a study was conducted

the extent to which the conclusions are true

what aspects are included in validity of a research article

population

design

results

outcomes

significance

population

process of selection, sampling, inclusion/exclusion criteria

study design

how the research was done

results

how they were analyzed and the statistical approach used

outcomes and significance

clinical, statistical

may not be statistically significant but it may have clinical importance

bias

was the study conducted so bias was minimized

internal validity

the degree of confidence that a casual relationship observed within a specific study is accurate and not influenced by extraneous factors or biases

threats to internal validity

bias

confounding variables

external validity

the extent to which the findings of a study can be generalized and applied to other populations, contexts, or situations beyond the specific research settings

threats to external validity

setting and timing

selection bias

other world events

factors that may affect validity

confounding variables

randomization

blinding

co-interventions

allocation concealment

bias

confounding variables

a third variable that confuses the relationship between the independent and dependent variable because it is associated with both

randomization

the process of assigning participants to a treatment group and a control group

it minimizes the differences by equally distributing among both arms of the study

blinding

part of a RCT where those involved are not aware of the assigned groups

single, double, or triple

placebo effect

if participants know which group they are assigned to there is a risk that they might change their behavior in a way that would influence results

single blinded

only particpants do not know what group they are in

double blinded

participants and investigators do not know who are in the groups

triple blinded

participants, investigators, and data analysts do not know who are in what groups

co-intervention

additional treatments or other interventions that are received that may affect the outcome of interest

can create bias if one group receives an intervention and not the other group

allocation concealment

a techniques in RCTs to prevent selection bias

hides the sorting of participants into treatment or control groups

used prior to onset of the study

why concealment is important

secures randomization and safeguards the group assignment

studies that lack concealment

overestimation of the treatment benefit by 20-40%

defeats the purpose of randomization

tend to yield biased results

bias

any systemic error that distors the findings and leads to inaccurate conclusions about the relationship between variables

reliability

how consistently a method measures something

if the same result can be achieved the study is considered reliable

ensuring the study’s results could be replicated again and again means it is reliable

applicability

the extent to which the research findings can be applied to - real-world situations, your patients population of interest, its impact on practice

limitations and resistance to EBM

studies have flaws

shortage of coherent consistent scientific evidence, and well done studies

bias

does it match your PICO perfectly

difficult in applying the evidence across the board or to your specific population

time factor of searching

threats to validity of research

sampling, randomization, and blinding errors

bias

conflicts of interest

random errors'

systemic errors

why do we care about sampling

the main component that influences the generalizability of clinical research findings is the sampling method

we take a sample of the population based on the sample we infer things about the populations

estimating an appropriate sample size produces studies capable of what

detecting differences

why are larger sample sizes better

they will behave more like the population would behave so more generalizable

too large of a sample amplifies what effects

emphasizes statistical differences that are not truly clinically relevant

statistical tests were developed to handle samples, not populations

when numerous cases are included in the statistics, analysis power is substantially increased

small sample sizes lead to what

lead to results that are not powerful enough to detect differences between groups

false negative-type II error

there may be an association between the variables, but you state there is not

low statistical power

how do you know what size is needed for a study

population size

margin of error

confidence level

population size

the total number in the population that you want to be able to generalize

margin of error

the amount of error youre willing to accept is okay

confidence level

the level of confidence you want to have in your results being accurate

what does sample size directly effect

reliability and extent to which yu can generalize those findings to the larger populations

probability

the sample population is selected in a systemic process

all subjects in the target population have equal chance to be selected in the sample

more representative of the overall target population

non-probability

the sample population is selected in a non-systemic process

does not guarantee equal chances for each subject in the target population

kinds of probability sampling

simple random

stratified

cluster

kinds non-probability sampling

convenience

snowball

simple random sampling

the entire population is used as the basis and a random generator based on chance selects the sample subjects

systemic sampling

a single random number is generated to determine the starting point, and individuals are selected at a specified regular interval until the sample is complete

stratified sampling

the population is divided into subgroups based on similar characteristics then you take the number of people from each subgroup that would represent the entire population

the goal is to ensure that the final sample includes each characteristics

cluster sampling

subgroups are created and each subgroup is representative of the population

convenience sampling

the most applicable and widely used method in clinical research

the investigators enroll subjects according to their availability and accessibility

quick, inexpensive, and convenient

snow-ball sampling

this method is sued when the population cannot be located in a specific place, and is difficult to access

the investigators asks each subject to give him access to others from the same population

preferred types of sampling

simple random sampling- gold standard, every person has an equal chance

stratified sampling - divides the group into smaller layers. best for making sure rare subgroups are counted fairly

cluster sampling- breaks population into natural groups. best for large, spread out areas

systemic sampling- picks every “nth” member from a list. best for ordered lists or time-series data

why is randomization important

allows results to be generalized to a larger population

removes personal bias

minimizes selection bias

balances characteristics and prognostic factors

ensures that data samples are fair, accurate, and truly reliable

why does blinding matter

information is withheld from one or parties to prevent bias