What are the 2 types of question in a clinical setting?

- background

- foreground

What are the 5 Steps to the EBP process

ask, access, appraise, apply, assess

What is a background question?

- general questions

- can come from the doctor or patient

What are foreground Qs?

- answerable clinical questions
- from patient and/or doctor
- ie. PICO

What are the realms of foreground questions

(PTHD)

- Prognosis - what was the observed outcome?
- Therapy - will a modality help?
- Harm - will exposure have an adverse effect?
- Diagnosis - will a particular test help me?

When is PICO formatting required?

for creating a foreground question

What does PICO stand for?

- Population/problem
- Intervention
- Comparison intervention
- Outcome of interest

What kind of studies help to answer foreground Qs

Primary studies

- RCTs for therapy related

What is a more practical source of information (other than Dr. Bhalaero)

Pre-appraised literature

What sites are useful for pre-appraised literature

- Dynamed
- TRIP
- Physiotherapy Evidence Database (more applications for Chiro)

When assessing the patient what are some questions you need to ask when it comes to pre-appraised lit.

- Did it help?

- Did it hurt?

What is the EBP Sandwich…

Meat/cheese - the take home question

Bread - how effective is the treatment

Bread - how good is the evidence

What is the pyramid of evidence for research? (from top to bottom)

GOD ->Systemic reviews ->RCT ->Cohort Studies ->Case-control ->Case-study/cross sectional ->Expert opinion ->animal studies

What are best answers for Therapy Qs?

RCT

What are the best answers for etiology and risk factor?

RCT, cohort studies, or case-control studies

What are the best answers for frequency and rate Qs?

cohort and cross sectional studies

What are the best answers for Diagnostic Qs?

cross-sectional studies

What are the best answers for Prognosis and Prediction Qs?

Cohort studies

What is an Observational study?

One in which the researcher is passive

What is an Experimental study?

One in which the researcher is active

What are observational cross-sectional studies

exposure and outcome are measured at the same time and once, like a snap shot in time

what are observational case-control studies

subjects with a specific outcome are matched with those without the outcome and info is obtained about their past exposure to a factor under study

Which study type is best for assessing risk factors or rare conditions?

case-control

What are observational cohort studies

data is obtained via exposure of 2 groups over time

What is considered the primary study in an Experimental Study?

RCT

What are the key components of a RCT?

- Allocation
- Randomization
- Baseline measurement
- Blinded intervention
- Blinded assessors measure outcomes

If the exposure/intervention was randomly allocated, the study is a ______________?

RCT

If the outcome was determined some time after the intervention, the study type was a ____________?

cohort study

If the outcome was measured at the same time as the exposure, the study was a _____________?

cross-sectional (snap shot in time)

If the outcome was measured before the exposure was determined, the study was a ______________?

case-control

A RCT requires what?

- large population sample
- randomization of treatment and control groups
- baseline measurements
- a treatment of interest
- monitoring

What are the key components of a RCT?

- inclusion criteria/exclusion criteria
- concealed allocation/baseline measurements
- treatment initiation/ongoing outcome assessment
- final outcome assessment/determination of treatment effect

Inclusion criteria

- defined characteristics that participants must have in order to be included in the RCT (ie. superpowers…sorry Ben Affleck Batman)

Exclusion Criteria

Characteristics that each participant cannot have in order to be included in the RCT (ie. liking vampires)

Randomization

makes sure there is a well distributed sample of the population in the groups of study

Monitoring Outcomes

moving forward in time; drop outs common

Realms of Appraisal

- How well has the study been conducted (internal validity)?
- What is the treatment effect?
- Is the treatment effect due to chance?
- Is the treatment effect clinically useful, especially given the patient’s unique perspectives and values?

Internal Validity

Are all the RCT parts there?

How well is each part done?

If a part of study is missing, does it fatally flaw the study?

Is it well done that you want to read more about the results?

ABCDFIX - “A”

Allocation

What happens when concealment allocation isn’t done?

40% overestimation!

Is concealment the same as randomizatio?

NO

Allocation best achieved by using what?

a centralized off-site computer allocation process

THE BEST allocation is done by using what?

a sealed opaque envelope

ABCDFIX - “B”

Blinding

The Big Three Blinded

Patients

Providers

Outcome Assessors

The Little Two Blinders

Statisticians

Adjudicators

ABCDFIX - “C”

Comparisons

What is important when doing a comparison?

- did they report a baseline

- did they correct for imbalances

Uneven attention in comparison

- # of treatments
- Amount of attention
- The Hawthorne Effect (more interaction with patients) and Placebo Effect

ABCDFIX - “D”

Drop Outs

Why is considering drop out important

- drop outs may be different
- could be a side effect
- stat power based on group size
- the randomized balance is lost
- it changes the math

5-20% rule

- under 5%: very limited risk of bias

- over 20%: high risk of bias

ABCDFIX - “F”

Follow Up

What is an ideal follow up period

- long enough for the study to be useful clinically

ABCDFIX - “I”

Intention to treat

The intention to treat principle

Once subjects are randomized they should be analyzed in the group they were first randomized, even if 1) they never received treatment, 2) discontinued the trial, 3) or crossed over to the other group

Why do an intention to treat?

prevents an overestimation of the treatment effect

ABCDFIX - “X”

X-factor…minus Simon Cowell

What 2 questions do you ask yourself once you decide to see if your RCT will help to answer PICO

- What do the results show?

- Could the results be due to chance?

Stats involve 2 key principles

- estimation

- inference

Estimation

- how big or small something is

- how big or small something is compared to something else

Concepts with Estimation

mean, median, mode - central tendency

standard dev. - measures of spread

Measures of Central Tendency

Mean - “the average”

Median - halfway point in a list on numbers

What is an outlier

data that doesn’t follow the pattern

What is skewness?

data not normally a perfect bell curve or normally distributed

WHat are the 2 outcome measures?

- Dichotomous outcomes - yes or no outcomes that either happen or don’t
- Continuous outcomes - outcomes that are potentially limitless and vary on a continuum

Reporting of results with dichotomous outcomes

- odds ratio or relative risk (RR)
- absolute risk reduction
- relative risk reduction
- number needed to treat

Reporting of results of continuous outcomes

effect size - difference between the treatment and control group means tells us how large or small the effect is

Inference

drawing conclusions (Bob Ross style)

Hypotheses

statement about the world that could be tested to see whether t is true or false

Confidence Intervals

more informative than p values

measure of spread or precision

an est. of the range of values that are likely to include the results of the study

P-value

>0.05 = stat insignificant - nothing going on <0.05 = stat significant

Confidence Intervals

- the narrower the better - larger studies have narrower CIs
- 95% confidence interval
- should not overlap the point of no effect (point where the null hypothesis is true)

Statistical Significance vs. Clinical Significance

Intervention only considered useful:

- 95% CI stat and clinically significant - clinical significance = size of the effect and the 95% CI in relation to a minimum effect that is clinically important (see graphs!!!!) (pg 10, 8/20/2013 packet)

Relative Risk

risk = chance of something happening RR = comparison of one risk to another

RR in a clinical world

is a comparison of risk outcome, desirable or not, in a treatment group compared to the risk of the same outcome in the control group

(= treatment group / control group)

What does an RR of 1.0 mean?

no difference between control and treatment

treatment neither decreases or increases the risk of event

What does >1.0RR mean?

- treatment group has a higher risk of the outcome than the control
- treatment increases the risk of event

What does <1.0RR mean?

- treatment group has a lower risk of the outcome than control
- treatment reduces the risk of the event

When would you reject the null hypothesis?

when a p value is less than 0.05

When would you accept the null hypothesis?

when the p value is above 0.05

Interpret RR = 0.5 in a RCT testing sunscreen on preventing skin cancer in Pheonix, AZ

- People who use sunscreen have less than a half chance of develop. melanoma
- people who do not use sunscreen have 2x greater risk of developing melanoma
- the rate of melanoma with sunscreen is 50% of the rate without

What is the relative risk reduction?

- the proportional decrease in event rates achieved by therapy
- impressively larger than the risk difference when the event rates are low

What is Absolute Risk Reduction?

the arithmetic difference in event rates achieved by therapy

What is Number Needed to Treat (NNT)?

# of patients needed to treat in order for only one of them to benefit ****the lower the NNT, the more effective the treatment

Calculating NNT (** QUESTION**)

100 / Absolute Risk Reduction (if given as a %)

1 / Absolute Risk Reduction (if given as a decimal)

Rule of thumb for NNT (** QUESTION**)

single digit NNTs for treatment applicable to chiro practice are considered effective treatments

Application questions

Is the treatment feasible?

what else do i need to apply this evidence?

what alternatives are available?

External validity

the application of evidence to individuals

External Generalizability

nature of your patients condition and how it relates to the study participants:

- phase/severity of injury
- age etc

What is PARQ

Procedures

Alternatives

Risks

Questions

Assessment

it is critical that you assess the effect on the patient and whther it 1) help? 2) hurt?

will you use it again?

the entire EIP process - was it easy? hard?, how can it be streamlined?