midterm 1 Flashcards

1
Q

what is the effect of the expectation on the result of the research

A

expectations can
dramatically distort our perceptions of
subjective measures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are example of the expectation on our health and what we think about the others

A

If we expect to feel better, our perception
of pain can improve by 30% or more
* If we expect others to feel better, many
of us we will see imaginary
improvements
* Conversely, if we expect to feel worse, we
will often imagine deteriorations in
subjective measure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what factors increase the expectations

A

Factors that can increase expectations
include the novelty, mystique,
sophistication, or simplicity of the
intervention, and the confidence or
friendliness of the practitioner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the blinding

A

One of the most effective methods for
minimizing expectation bias is to
conceal the identity of the treatment
from both the participants and
researchers until the trial has ended
– this is known as blinding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the two steps factors in blinding

A

Two important steps in blinding are:
* Making the treatments as similar as possible in appearance, odour,
flavour, etc., so participants and researchers cannot tell them apart
* Replacing the treatment labels with codes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

can blinding reduce the exaggeration

A

Blinding can markedly reduce exaggeration:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

who should be blinded as possible

A
  • Participants
  • Healthcare providers
  • Data collectors
    (those who record symptoms, measure things like BP, administer surveys, etc.)
  • Outcome adjudicators
    (those who decide if a participant has experienced the primary outcome)
  • Data analysts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

do authors need to mention which group is blinded

A

Authors should explicitly state which groups are blinded instead of
using vague ‘single/double/triple-blind’ terminology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what we need to check to find that the research did the double blinding

A

1.The similarity of the treatments The treatments should be described in detail. You should be able to tell if they are sufficiently
similar to prevent people from figuring out who is receiving what
2. Who was blinded – are specific groups named, or is the description vague (e.g., ‘double-blind’)?
Look for mention of participants, treatment providers, etc.
3. If blinding was not possible or not done, check the outcome:.OK if the primary outcome is objective (e.g., a number, like mortality)
A fatal flaw is if it is subjective (e.g., a pain score, a survey) the unblinded study is useless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the unrelated reasons that somebody drop out of the research trial

A

Not everyone who enrols in a trial continues to participate until the end
Some stop participating for reasons unrelated to the treatment:
* They move away
* They develop a new medical condition that precludes ongoing participation
* They simply don’t want to bother
* etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are some related reasons for dropping out of the research trial

A

Some drop out because of the treatment:
* They develop an adverse effect that they find intolerable
* In rare cases, a participant may die because of the intervention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what ignoring the dropped out people can cause distort the result

A

If those who drop out of a trial before it finishes are ignored, the results can become distorted in several ways:
1) Randomness can be lost, which can alter the results considerably
2) The sample size may become too small, resulting in an underpowered study
3) Severe adverse effects can be hidden

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the per-protocol analysis

A

if we only included those who followed the entire protocol, this is called a ‘per protocol’ (PP) analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the intention to treat ITT analysis

A

if we included everyone who we
intended to treat, this is called an ‘intention-to-
treat’ (ITT) analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

which analysis would CONSORT recommend ITT or PPT? why?

A

CONSORT recommends that an intention-to-
treat analysis always be presented, because it:
* maintains the random distribution of
confounding variables between groups
* maintains sample size & power
* is less likely to miss relevant adverse effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why the PPT is not acceptable

A

a per-protocol analysis can:
* result in uneven losses of confounding
variables from the groups, biasing the
conclusions
* cause a loss of sample size & power, biasing
the conclusions
* conceal relevant adverse effects, since anyone who withdraws (or dies!) due to severe adverse effects are not taken into account

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

in what situation a PP is acceptable

A

PP is acceptable in addition to, but not instead
of, ITT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

when the PP is appropriate

A

PP may be appropriate if there are few losses
and they are not related to the intervention
(e.g., pregnancy, moved away, etc.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

when the ITT is required

A

An ITT analysis is required if any of the following apply:
* Some participants died due to the treatment
* Some dropped out due to adverse effects of
the treatment
* Some left for unknown reasons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

why do we need flow chart

A

To make it easier for the reader, CONSORT
recommends that all RCTs include a flow chart
showing how many people were randomized into each group, how many dropped out, and how many completed the trial
In addition, reasons for all losses should be
provided directly on the flow chart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what we need to check in the RCT to know which analysis was used

A

What to check in an RCT:
1. Look for a flow chart showing losses, with reasons.
If some losses are related to the intervention (adverse effects; deaths) or are ‘unknown’,
analysis should be ITT
2. Check the type of analysis
Check # in each group at beginning & end of trial  which number was used in the analysis?
Has everyone been accounted for? (I.e., has an ITT analysis been performed?)
(Caution: Authors may wrongly call a per protocol analysis “modified ITT” or simply “ITT”)
3. Losses should be modest
Arbitrary rule of thumb: Concern if losses >10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the assessing interpretation mean

A

Assessing ‘interpretation’ in an RCT means looking at the authors’ conclusions to see if they are justified by the data presented in the study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the three things that affect the interpretation of the data

A

1) Exaggeration
2) Surprising results
3) Limitations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

explain the exaggeration

A

Exaggeration
As we have seen, exaggeration is common in the medical literature
It is therefore important to take a moment to check if the conclusions drawn by the authors are supported by the data presented in the RCT If they say they found an effect, look at the data to see if the groups were actually significantly different – sometimes they are not!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is the Surprising results

A

If the authors find something that conflicts with what is known on a subject, the onus is on them to explain why we should believe their
results rather than the existing evidence
This is particularly important if the contradictory evidence is strong Therefore, the authors should provide a brief review of the existing
evidence, and comment on any apparent contradiction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is study limitation

A

Study Limitations
CONSORT recommends that authors include a heading called “Limitations” to ensure that the reader is aware of the study’s weaknesses
The authors should explain how the limitations could have affected the results. in some cases no conclusions about efficacy can be drawn because of a severe deficiency Study authors sometimes describe weaknesses that are essentially fatal flaws, but then ignore them when drawing their conclusions The reader of an RCT should therefore look at the study’s limitations to see if
(1) they are easy to find, and (2) there are any weaknesses that render the
conclusions doubtful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what do we need to check to have a good interpretation of the data

A

Do the data in the tables and figures support the conclusions?
If the conclusions are not supported by the data, don’t accept them
 Have the authors reviewed the existing evidence?
If their new findings are contradictory, the onus is on them to explain
why they are correct and previous researchers are wrong
 Have the authors ignored serious limitations?
If the authors tell you of a serious flaw in their study that may make it impossible to draw any firm conclusions, they should take it into account when drawing their conclusions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is CONSORT stand for

A

Consolidated Standards of
Reporting Trials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

when CONSORT was published and when it was edited for the first time

A

Published 1996; substantial update
2001, minor edits 2010 (current
version)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the RCT is dicribing

A

The clarity with which an RCT is
described is known as ‘quality of
reporting’ (QOR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the CONSORT and why do we need it in the RCT

A

CONSORT identifies 25 items that
should be clearly described in any RCT
Purpose is simply to allow the reader to
know what was done (whether the trial
was done well or poorly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the triage in the medical term

A

Triage is a medical term:
‘To sort patients according to the seriousness of their injuries or illnesses’

33
Q

how we sort patients

A

Non-urgent – can be attended to later
* Serious but not immediately life-threatening
– can wait a bit
* Life-threatening – requires immediate treatment

34
Q

why RCT show the effectiveness of the trial

A

In contrast to other study types, RCTs can reveal the effectiveness of a
treatment because:
1) The control group reveals the effects of natural, in-born healing
mechanisms, so that we do not mistakenly give credit for their effects to the therapy we are testing, and
2) Confounding variables, such as individual differences in natural healing ability, are randomly – and presumably evenly – distributed
between the groups, so that the only explanation for a difference in
outcomes between groups is the treatmen

35
Q

what are the observation or association studies and are they associated with the uncertainty

A

‘observational’ or ‘association’ studies)
can reveal possible links between a therapy and an outcome, but there is uncertainty – because the participants were not randomly assigned to the groups, there might have been another, unevenly distributed a factor that caused the outcome, instead of the interventio

36
Q

can we use the association studies to demonstrate the causal relationship

A

association studies cannot be used to
demonstrate causal relationships

37
Q

what are the first iteams to look at the CONSORT

A

4a – Participant eligibility criteria
15 – Baseline data
21 – Generalizability

38
Q

the conclusions of an RCT should be aimed at what kind of the population

A

The conclusions of an RCT should be aimed at a population that is similar to the participants in the study

39
Q

what we need to check in the RCT to know that the conclusion is aimed to the population similar to the participants

A

 Eligibility
There should be a clear description of who was eligible to participate
Often given in the form of ‘inclusion criteria’ and ‘exclusion criteria’
 Baseline data
A table should be provided giving a detailed description of the
participants
 Generalizability
Look to see if the conclusions are aimed at a population similar to the
participants in the study

40
Q

what is the out come in the clinical trial

A

An outcome is the parameter that is measured in a clinical trial, such as blood pressure, survival, days to recovery, pain intensity, etc

41
Q

what is the result of the proper handling the outcome

A

Proper handling of outcomes in an RCT helps to minimize the risk of a false positive result

42
Q

what does “When we compare treatments, we start with groups that are as similar as possible” means

A

When we compare treatments, we start with groups that are as similar as possible:
* Similar in ability to heal from the disease being studied
* Similar in their responses to treatment
These are hidden confounding variables, and we attempt to distribute them equally between groups by placing participants into the groups randomly If these confounders are equally distributed, then the intervention should be the only possible cause of any difference
in the outcome we measure

43
Q

why the risk is highest if the sample size is small:

A

Small groups of people may differ in their ability to mount an antibody response, the robustness of their inflammatory response, their ability to produce interferon, etc., and one group may recover from the illness being studied more
rapidly than the other

44
Q

what is the false positive result

A

An ineffective therapy could appear to
be effective simply because the
groups were different at the start of
the trial (e.g., different in ability to
heal naturally or fight off an infection)
This is known as a false positive result

45
Q

what is the relationship between the group size and the healing ability

A

The larger the group size, the smaller the risk that there will be a significant difference in healing ability between groups

46
Q

why we cant use the infinitely large groups

A

But we can’t use infinitely large groups, so we need to decide how big a risk we are willing to accept that we will see a false positive result in the trial we are performing (called ‘alpha’)

47
Q

how much risk do scientists accept

A

Most scientists accept risk of 5% (alpha = 0.05) In other words, one in every 20 trials will be misleading because they will show a difference between groups that is not
an effect of the treatment, but simply a result of the fact that one group was better than the other at healing naturally Did the authors identify a primary outcome? Are the conclusions based on it?

48
Q

what is the basic error about the risk of the false positive result

A

And here is where one of the most basic errors in a clinical trial can be made: not realizing that the 5% risk of a false positive result applies to just one measurement If you measure two things, each with a 5% risk of a false
positive, the chance that you will see a false positive result in one of the two measurements is ~10% Some researchers measure dozens of clinical parameters, essentially ensuring that they will see a false positive result, but mistakenly assume that the risk is still 5% and conclude that any difference observed is an effect of the intervention

49
Q

what is the secondary outcome use for

A

Secondary outcomes can be measured in order to:
* collect non-efficacy information (E.g., about adverse effects)
* support the primary outcome or cast it into doubt (E.g., if a drug really does improve one CVS parameter, one might also expect it to improve other CVS parameters. If this happens, the secondary outcomes lend support to the primary finding. If this does not
happen, it suggests that the primary finding might be a false positive)
* provide ideas for future trials (the current secondary outcome would be the new primary outcome) Conclusions regarding secondary outcomes should be tentative

50
Q

how we can look for the primary outcome in the article

A

Has a primary outcome been identified?
If more than one parameter is measured, a primary outcome should be clearly identified
 Are conclusions based on the primary outcome?
Conclusions about effectiveness that are based on another measurement
(i.e., a secondary outcome) are not valid
 Red flags
Studies with no specific primary outcome, in which many parameters are measured,
are likely to mistake false positives for treatment effects:

51
Q

In addition to identifying a
the primary outcome, authors should
also:

A

In addition to identifying a
the primary outcome, authors should
also:
* Report the results for all outcomes that were
measured
* Provide confidence intervals, not just p-values
* Provide absolute values, not just percentages
* Compare the means of groups to one another, rather than comparing the mean in
each group to the initial (baseline) value in that group

52
Q

why Confidence intervals are more
informative than p-values

A

Confidence intervals are more
informative than p-values
P-values indicate the likelihood that
the difference between groups is real
(i.e., not a false positive), but do not
indicate how large (important) it is
P-values also place too much
emphasis on the mean

53
Q

how can we interpret the confidential intervals

A

The way to interpret a CI is to
recognize that the true effect is
likely to lie somewhere within
the range, and not necessarily in
the middle

54
Q

what does 95% confidential interval means

A

We usually use 95% confidence
intervals, meaning that 95% of
the time the real effect will lie
somewhere within the
calculated confidence interval

55
Q

how we can interpret the Cl croosses lines

A

If the CI crosses the line of
no effect, we conclude
that the intervention is not
effective, regardless of the
mean value
For these reasons, the
results of trials that report
only means and p-values
are less informative than
those that report
confidence interval

56
Q

A sample size calculation is needed in order
to know:

A

1The risk that any difference observed
between groups is spurious (false positive)
2The risk that a real difference between
groups may have been missed (false
negative

57
Q

how much of risk of false positive and false negative do scientist accept

A

Scientists usually accept a 5% risk of a false
positive and a 10-20% risk of a false negative

58
Q

what are the variables for the sample size

A

Look for alpha, power, effect size, and variance as evidence that a
calculation was actually performed

59
Q

What is allocation concealment?

A

It is a poorly understood step in an RCT
that is often ignored
It is any procedure that prevents the
researchers who place the participants
into groups from knowing which
treatment each participant will receive

60
Q

what happens if the researchers who place (i.e., ‘allocate’) the participants into the groups are aware of the treatment each will receive

A

If the researchers who place (i.e., ‘allocate’)
the participants into the groups are aware of
the treatment each will receive, it would be
possible, either deliberately or
subconsciously, to place those who look
sickest into one group and the healthiest
people into the other group
The results of such a trial could be severely
exaggerated

61
Q

Two common third-party methods:

A
  • Pharmacist
    Send the test drug to a pharmacist, who
    makes a matching placebo, places them
    into vials encoded according to a
    random sequence supplied by the
    researchers, and returns the coded vials
  • On-line allocation system
    The patients’ names are entered, and
    the computer randomly assigns them to
    groups
62
Q

is it important to mention that that the person who allocated the participants had no role in the study

A

It is helpful if the authors of the RCT
also make it clear that the person
who allocated the participants had no
other role in the study (such as
generating the random sequence), to
further minimize the possibility of
tampering

63
Q

what we need to do insted of third party allocation is not employed

A

If third-party allocation is not employed,
the use of Sequentially Numbered
Opaque Sealed Envelopes (SNOSE) is
better than nothing

64
Q

what does SNOSE stands for

A

Sequentially Numbered
Opaque Sealed Envelopes (SNOSE

65
Q

what does it means if the RCT makes no mention about the related allocation concealment

A

If an RCT makes no mention of anything
related to allocation concealment, it
suggests that the researchers were not
aware of the issue and the risk of bias is
high

66
Q

how can we search for the allocation concealment

A

Indicators that they did it well
Try Ctrl-F for words like ‘allocation’ ‘centralized’, etc.
Look for mention of ‘third-party’ allocation
(e.g., a pharmacist, on-line allocation tool)
 Did they mention Sequentially Numbered Opaque Sealed
Envelopes (SNOSE)?
This is not as secure as third-party allocation, but can be effective if
employed properly

67
Q

The most effective way to distribute these traits evenly is to do so according to…………..

A

The most effective way to distribute these traits evenly is to do so according to a random sequence

68
Q

how to Random allocation procedure

A

Random allocation procedure
1) Random sequence generation
2) Allocation concealment
(Distribute participants into groups according
to sequence, without knowledge of treatment)

69
Q

what is the simple randomazation

A

Simple
Randomized one by one (e.g., coin flip)
Appropriate for groups 100+

70
Q

what are two types of the Restricted randomizations

A

Blocking
Link detectable confounders into a
block and then randomize block
Stratification
Place detectable confounders in
different groups and then
randomize each group separately

71
Q

what we should consider befor applying an intervention into clinical practices

A

In order to determine whether an intervention should be used in clinical practice, it is important to weigh its potential benefits against
its potential harms

72
Q

can all the substances produce the toxicity

A

All known substances can produce toxicity: the dose is the difference between a drug and a poison, or a foodstuff and a poison (even
water in excess can be fata

73
Q

what are the recommendations that an RCT include for the toxicity and harmfulness of a drug

A

CONSORT recommends that an RCT include a table showing the number, type, and severity of harms in each group
All adverse effects that were observed should be reported, leaving it to the reader to decide which ones were probably caused by the treatment.
To make it easy to locate this information, CONSORT recommends that the heading “Harms” be included
CONSORT further recommends that the harms and benefits be discussed together and weighed fairly in the conclusions

74
Q

how we can check harm in the CRT

A

Is there a heading called “Harms”?
Reader should not have to hunt for this information
(Entitled “Harms” rather than “Safety”)
 Do they provide a table with detailed information?
Should report all observed harms so reader can judge likelihood of a link to the intervention
 Do they balance harms and benefits when drawing conclusions?
Or do they make vague or dismissive statements about harms (a flag)
E.g., do authors list serious adverse effects but then ignore them when drawing conclusions?

75
Q

what is the Conflict of interest:

A

A situation in which a person is in a position to derive personal benefit from actions or decisions made in their official capacit

76
Q

compare industry funded research to the government or not for profile researches

A

industry can perform high-quality research, but as we have seen, industry-funded studies were four times as likely to draw favourable conclusions that were not justified by the data,
compared to studies funded by government agencies (e.g.,NSERC, CIHR) or non-profit organizations (e.g., Heart & Stroke
Foundation, Canadian Cancer Society)

77
Q

when the conflict of the interest arise

A

A conflict of interest may also arise if the
researchers have received personal fees in the
past from the funder
Personal consulting fees from industry sometimes exceed a university scientist’s annual salary, and those conducting an RCT may feel pressure to please the
funder in order to ensure such fees continue
Similarly, scientists who are employees of the
funder may feel pressure to please the funder
Bias arising from such situations may be
deliberate or (in many cases) subconscious

78
Q

how we can look for a source of funding

A

Look for source of funding
Lowest risk of funding-associated bias with non-profit sources
 Look for involvement of any for-profit funder in the research
Check author affiliations & ‘Conflict of Interest’ statement
Risk of bias is high if authors are employees or paid consultants of the funder, or if
company helped with the research (performed some of it, analyzed data, wrote or edited
manuscript, etc.)
 There should always be a conflict-of-interest statement (may be called ‘Disclosure’, etc.),
even if no conflict exists; can’t just assume  risk of bias is high if no statement is made

79
Q

why most research finding are false

A

Smaller studies are
more likely to give
false results.
Smaller effects are
more likely to be
false.
The more things
that are tested, the
more likely some
are to be false.