Vitamin C in patients with cardiac arrest (VITaCCA): a RCT

Question 1

What was one of the first RCTs?

Answer 1

An RCT where people with scurvy were administered different kinds of ‘treatments’ (i.e. only water, only oranges/lemons, apple cider, beer or honey(?)). The one that got administered oranges and lemons, was the only one to survive.

Question 2

Name some characteristics of an RCT.

Answer 2

• Prospective (following patients forward in time)
• Randomly allocated to intervention or control group
• Follow up until finite date or 1 or more outcomes of interest

Question 3

What are strenghts of an RCT?

Answer 3

• Ability to evaluate causal relationships
• High internal validity
• Investigator control over patient exposure
• Prospective data collection, which allows for standardization of exposure and outcome collection
• Attempted balance, through randomization, between known and unknown confounding factors between groups

Question 4

What are limitations of an RCT?

Answer 4

• Higher cost than observational studies
• Limited external validity and generalizability, due to strict inclusion and exclusion criteria and application of interventions by protocols
• Ethical considerations related to assigning patient to particular care approaches
• Generally shorter-duration follow-up than observational studies
• Inefficiency of detection of rare or delayed outcomes, due to smaller sample size and shorter-duration follow-up than observational studies.

Question 5

What is PICOT?

Answer 5

It is the formulation of a research question. It stands for: Patients, Intervention, Control, Outcome and Timing.

Question 6

What can be important when generating inclusion and exclusion criteria for an RCT?

Answer 6

A balance between generalizability and minimization of bias.

Question 7

What is the difference between block and stratified randomization?

Already question that was discussed in previous lecture.

Answer 7

• Block randomization → ensures a relatively equal number of patients randomized to each group
• Stratified randomization → ensures balancing of key baseline characteristics between groups

Question 7

What is deferred consent?

Answer 7

Deferred consent will only occur when an emergency procedure or therapy ‘needs’ to occur (for research). At this emergency, the patient is incapable of providing informed consent and their legal representative is also incapable of providing consent. Then study procedures are temporarily undertaken without consent, as soon as possible, written constent from the patient or legal representative is sought. If afterwards the patients or legal representative refuses to give consent, the data of this particular participant can not be used for research.

Question 8

What is important to take into considerations regarding data collection?

Answer 8

• Patient characteristics (balanced?).
• If possible, collected as continuous data rather than categorical.
• Preferably blinded data collection.

Question 9

Current evidence-grading systems are biased towards RCTs, which may lead to inadequate consideration of non-RCT data.
What are objections to observational studies (which of many are misconceptions that have been dispelled by studies)

Answer 9

• Potential for bias from unrecognized factors
• Overestimation bias