WHY WE NEED RANDOMISED CONTROLLED TRIALS

Question 1

what is evidence based medicine?

Answer 1

the application of the best available research to clinical care, which requires the integration of evidence with clinical expertise and patient values.

Question 2

what are the 4 stages of clinical trial reporting?

Answer 2

1) Register with a Trials Registry
2) Brief summary of results
3) Full results and methods
4) making individual patient data available

Question 3

what is a clinical trial?

Answer 3

A planned experiment involving patients, designed to determine the most appropriate treatment of future patients with a given medical condition

Question 4

what is phase 1 of a clinical trial?

Answer 4

using a small number of healthy volunteers to test safety and tolerance

Question 5

what is phase 2 of a clinical trial?

Answer 5

using patients to test efficacy, safety and tolerability

Question 6

what is phase 3 of a clinical trial?

Answer 6

using a therapeutic dose on patients to test for effectiveness in clinical practice

Question 7

what is phase 4 of a clinical trial?

Answer 7

using a therapeutic dose on patients but no control group, to check for effectiveness and safety in the long term.

Question 8

what is historical control? what are the problems with using it?

Answer 8

where old data is used to compare with new data from new trials.
they might not be a similar group of patients, the disease might be different, has the way we assessed treatment changed, are there new guidelines?

Question 9

what are before/after studies?

what is the main issue with the before/after study designs?

Answer 9

evaluating the effects of a deliberate intervention by comparing the outcomes of study participants investigated before the intervention with those measured afterwards.

regression to the mean and there are some temporal effects

Question 10

what is regression to the mean?

Answer 10

A phenomenon that occurs when a group are measured with an inexact measurement tool and then re-measured. Individuals with ‘extreme’ values will have a high probability of regressing towards the mean on the second measurement.

Question 11

what are concurrent controls?

Answer 11

both groups receive control/intervention at the same time but it’s not random, there is some way of assigning people to their groups.

Question 12

why is randomisation in trials important?

Answer 12

it eliminates systematic bias, it helps ensure balance across comparative groups, differences in outcome can be attributed to intervention only, it is more ethical.

Question 13

what is stratification?

Answer 13

the arrangement or classification of something into different groups

Question 14

what is bias?

Answer 14

Systematic distortion of the estimated intervention effect away from the “truth”, caused by inadequacies in the design, conduct, or analysis of a trial.

Question 15

what is selection bias?

Answer 15

Systematic error in creating intervention groups, such that they differ with respect to prognosis

Question 16

what is ascertainment bias?

Answer 16

Systematic distortion of the results of a randomised trial as a result of knowledge of the group assignment by the person assessing outcome, whether an investigator or the participant themselves.

Question 17

what is performance bias?

Answer 17

Systematic differences in the care provided to the participants in the comparison groups other than the intervention under investigation

Question 18

what is allocation concealment?

Answer 18

A technique used to prevent selection bias by concealing the allocation sequence from those assigning participants to intervention groups, until the moment of assignment.

Question 19

what are cluster RCTs?

Answer 19

involve randomisation of groups (clusters) of individuals to control or intervention conditions. The CRT design is commonly used to evaluate non-drug interventions, such as policy and service delivery interventions.

Question 20

what is effect size?

Answer 20

a statistical calculation that can be used to compare the efficacy of different agents by quantifying the size of the difference between treatments

Question 21

what is minimal clinically important difference?

Answer 21

the smallest amount an outcome must change to be meaningful to patients.

Question 22

what is it called when there are too few/too many subjects in a trial?

Answer 22

underpowered sample size

overpowered sample size

Question 23

describe the difference between ‘intention to treat’ analysis and ‘per-protocol’ analysis?

Answer 23

ITT analysis includes every participant- aims to act like a real world setting
PP analysis using using participants who completed the study without any major protocol violations

Question 24

how should all new treatments be evaluated?

Answer 24

with an RCT design