lecture 6: RCT Flashcards

1
Q

what are the types study designs under experimental studies th

A

RCT
cross over
quasi-experimental
single-subject

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2
Q

true or false:Rct is the ideal design for evaluating both efficacy and effectiveness of a treatment

A

truewh

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3
Q

what is the major advantage of RCT over observational

A

ability to demonstrate causality

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4
Q

where do RCT rank in the levels of evidence

A

1a) systematic review of RCTS
1B) individual RCT with narrow confidence intevential
2b) low quality act with loss to follow up

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5
Q

what would make an RCT level 1b

A

narrow confidence interval (not much variability in results), not a lot of loss to follow up

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6
Q

what are some reasons you would have a low quality RCT

A

wide CI
loss to follow uo
randomization issues

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7
Q

true or false: RCTS are retrospective and experimental

A

false, they are prospective and experimental

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8
Q

what does it mean that an RCT is a prospective and experimental study

A

starts at a point in time and progresses foreard
the intevention/IV is controlled by the investigator

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9
Q

true or false: RCTS are usually comparative studies

A

true

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10
Q

the comparison group[ is an RCT is aka

A

control group

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11
Q

what is the basic design model of an RCT

A

CONSORT diagram

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12
Q

explain the consort diagram

A

Start with population of interest and use an eligibility criteria to establish who is eligible/non elig (excluded).

The eligible people will be contacted to engage in the study (recruitment) and a part of them will decline to participate (not part of the study even tho they are eligible). The sample of the study will only include those who agred to participate and signed the informed consent.

Then we have the randomization (most important feature of the RCT because it controls for potential counfounders) into eather the intervention or the control group/usual standard of care/no intervention (all depends on the ethics).
Groups are followed over time to see if there is any difference between the groups (look to see if there is a mean difference in the effect on that particular outcome of interest)

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13
Q

why may RCTs be difficult in terms of ethics

A

RCTS can be challenging for ethical aspects (hard to convince people to be part of a control etc) that is why many of the studies are quasiexpreimental

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14
Q

what is a quasi experimental study

A

in a quasi-experimental study, the researcher still manipulates an independent variable but does not have full control over some aspects of the study such as no randomization, sometimes no control group (only intervention)

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15
Q

where does RCT fit in the research cycle

A

they establish efficacy. effectiveness and efficiency

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16
Q

where does cohort fit in the research cycle

A

mecs and associations

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17
Q

where does case control fit in the research cycle

A

mec and assocaiton

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18
Q

where does cross-sectional fit in the research cycle

A

burden of disease

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19
Q

what is the def of efficacy

A

refers to the ability of an intervention to produce a desirable effect under ideal/controlled conditions

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20
Q

what is the def of effectiveness

A

refers to the ability of an intervention to produce a desirable effect in the real world setting/clinical practice

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21
Q

what is a a reason that you might have 100% efficacy in the lab but only 50% effectiveness in the health setting

A

because in the real world you have many factors that influence outcomes effect such as access to care, how many people to deliver the care, instrucments etc)

efficiency is done with ideal circumstances, perfect compliance, adherence to protocols, and use per protocol analysis, this differs from effectiveness trials that have real world circumstances, compliance is self determined and protocol violations may occur

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22
Q

true or false: if a study has 100% efficacy and 100% effectiveness, that means we will automatically implement it as a treatment and explain

A

false, it is not just about having the presence of an effect but also about the efficiency and resources. For a study to be implemented it must also have optimal use of ressoruecs such as (time, money, feasibility etc)

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23
Q

what are the 5 main features of an efficacy trial

A

ideal circumcanstances
perfect subject compliance
no protocol violation
endpoints on all data
per protocol analysis

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24
Q

what are the 5 main features of an effectiveness trial

A

real world circumcanstances
compliance self -determiend
protocol violations may occur
missing data
intention to treat analysis missing data inputed

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25
Q

what does it mean for an efficacy trial to have ideal circumstances

A

This refers to conducting the trial under optimal conditions that maximize the likelihood of observing the effects of the intervention being tested (standardized measures, controlled environments and controlled confounding variables)

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26
Q

what does it mean for an efficacy trial to have perfect subject compliance and no protocol violation

A

Subject compliance refers to the extent to which participants adhere to the study protocol, including following instructions, taking medications as prescribed, attending follow-up appointments, etc. In an efficacy trial with perfect subject compliance, every participant would strictly adhere to the protocol without deviation

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27
Q

what is a per-protocol analysis in efficacy trials

A

Per protocol analysis involves analyzing only the data from participants who strictly adhered to the study protocol, excluding those who deviated or dropped out.

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28
Q

what does it mean for an effectiveness trial to have real-world circumstances circumstances

A

Real-world circumstances also include factors such as variations in healthcare delivery, resource availability, and patient-provider interactions that can influence treatment outcomes.

29
Q

what does it mean for an effectiveness trial to have compliance self-determined

A

Unlike efficacy trials where subject compliance is closely monitored and often enforced, participants in effectiveness trials have more autonomy in determining their level of compliance with the intervention.

30
Q

what are some reasons for missing data in effectiveness trials

A

participant dropout, loss to follow-up, or incomplete data collection.

31
Q

what is intention to treat analysis

A

participants are analyzed based on their initial treatment assignment, regardless of whether they actually received the treatment or not.

This approach is simple and important because it helps maintain the integrity of the randomized treatment assignment

32
Q

why is intention to treat anaylsis important in RCTS

A

This approach is simple and important because it helps maintain the integrity of the randomized treatment assignment (if you just excluded the data, the sample could potentially be biased./not representative_

33
Q

how do you read an RCT

A

research question
consort diagram
demographic tables
results tables

34
Q

how are the results tables usually represented in RCTS

A

p values, CI, effect size

35
Q

in an RCT, If the study’s aim is to provide evidence the question must be BLANK

A

specific as to what evidence is needed

36
Q

what are some of the questions that should be answered by the RCT research question

A

PICOT :
Who should be studied?
What should the intervention be?
What should the comparator be?
What should the outcome be?
When should the outcome be measured?

37
Q

know the table for the PICOT model in RCTS

A
38
Q

what is the consort diagram

A

flow diagram displaying the process of all participants through the trial

39
Q

the consort diagram is a useful tool for detecting what type of bias

A

selection bias

40
Q

know the important elements of a consort diagram

A
41
Q

in the consort diagram, you see that the sample size in the intervention group is 44. They then lose 4 people to follow up, but the analyzed sample is still 44. What does the mean/what analysis did they use

A

intention to treat analysis (did not exclude the missing data)

42
Q

true or false: efficacy trials will ONLY use per protocol analysis

A

false, they normally use that but sometimes will use the intention to treat because realistically people can drip out and the intention to treat protocol will maintain the prognostic balance that the randomization provides

43
Q

true or false; demographics table is done at baseline

A

false

44
Q

what are some things to look for in the demographics table

A

look for baseline similarities between groups (want the groups to have no statistically significant differences in their characteristics)
-look at p values

45
Q

what are the 3 main important results i the results table

A

p value
CI
effect size

46
Q

what is the CI (give example of what a 95% CI means

A

a reliability interval estimate that suggests the range of outcome results when the analysis is repeated

ex:With similar study samples, we would expect that the mean value difference b/w the groups would lie anywhere between the CI boundaries 95 out of 100 times.

47
Q

what does a p value of 0.05 indicate

A

there is a 5% chance that the results are due to chance and not the effect of treatment

48
Q

true or false: the p value tells you how much better the intervention is when compared to the control…

A

false, it does not

49
Q

if a value is statistically significant, then it is also clinically significant

A

false,

50
Q

is p value influenced by sample size and explain

A

yes
With a sufficiently large sample, a statistical test will almost always demonstrate a significant difference Because larger sample sizes enable us to/more powerful to detect even small differences between the groups

51
Q

what is a benefit/advantage of the CI in terms of comparing it to ur intervention

A

95% CI allows you to see the change of the intervention in the units of the measured variable (same unit as the outcome measure units) which helps determine significance clinically

52
Q

a result is not statistically significant if the CI includes what

A

null value

53
Q

in an RCT, a result is not statistically significant if the CI includes…

A

0

54
Q

in an case control and cohort, a result is not statistically significant if the CI includes…

A

1

55
Q

why is the null value for an RCT 0 and not 1

A

null value is 0 because we are looking at a difference in means between a control and intervention group

56
Q

what does the size of the CI deepen on

A

sample size and standard deviation

57
Q

explain the effect of a large sample size on CI

A

Large N = “more confidence/precision” = narrower CI

58
Q

explain the effect of a smalll sample size on CI

A

Small N = “less confidence/precision” = wider CI

59
Q

what does the effective size measure

A

the magnitude of a difference in mean between treatment and control groups
Independent of sample size

60
Q

0.2-0.4 is a small, moderate or strong/large effect size

A

small

61
Q

0.5-0.7 is a small, moderate or strong/large effect size

A

moderal

62
Q

0.8 and above i a small, moderate or strong/large effect size

A

large

63
Q

what would be a large cohend d effect size

A

0.8 and above

64
Q

what would be a moderate cohend d effect size

A

0.5-0.7

65
Q

what would be a smal cohend d effect size

A

0.2-0.4

66
Q

what is the between group comparison of a study (CHAT GPT and notes)

A

Between-group comparison in studies involves comparing two groups (intervention and control) to evaluate differences in outcomes of interest/efficacy of intervention

67
Q

what is the within group comparison of a study (CHAT GPT and notes)

A

Within group comparison is used to determine the change in the outcome of interest within 1 group

68
Q

what dopes CMC mean

A

clinical meaningful change :

refers to the degree of change in a measured outcome that is considered significant or relevant from a practical/clinical standpoint,

69
Q

basic form for interpreting CI and mean change

A

-comment on true mean change between groups (name the groups, the unit and the CI)
-state what the CI means in words
-mention if the CI is statistically significant/and or clinically significant
-mention if the confidence interval is narrow/wide and pqrescicion deepening on clinical relevance.
-make a conclusion about the results of the the study/intevention