This document provides an overview of critical appraisal of randomized controlled trials (RCTs). It defines critical appraisal as carefully examining research to assess its trustworthiness and relevance. RCTs are described as the gold standard for clinical trials, where participants are randomly allocated to groups that receive either a treatment or a control. Key factors to examine in appraising an RCT are described, including sample size, eligibility criteria, baseline characteristics, randomization, blinding, follow-up of participants, data collection, presentation of results, and applicability to local populations. Advantages of critical appraisal and RCTs include providing a systematic way to assess research validity and improving practice, while disadvantages include taking time and not always finding clear answers.

1. Critical Appraisal of
Randomized Controlled Trials
Done By
K.H. Dhiwahar . MPT (sports)
P. Saba kannan raja .MPT (sports)

2. INTRODUCTION
 The skill of critical appraisal that allows the reader to
identify inconsistencies, assumptions, in the research
process, and then balance these against the outcome
of the research .
 Critical appraisal is the process of carefully and
systematically examining research to judge its
trustworthiness, and its value and relevance in a
particular context.
 In order to decide whether the outcome has value and
reliability, and can underpin a clinical decision.

3. CLINICAL
EXPERIENCE
PATIENT
PREFERENCE
EVIDENCE

4. Critical appraisal is an important element of
evidence-based medicine. The five steps of
evidence-based medicine are:
Comparison
outcomes

5. Hierarchy of evidence
RCT

6. Randomized Controlled Trials ( RCTs )
 RCT is a specific type of scientific experiment, and
the gold standard for a clinical trial. RCT are often
used to test the efficacy and/or effectiveness of
various types of medical intervention within a
patient population.
 Population is randomly allocated to two groups
 One group is given a specific treatment or
intervention
 On average the groups are identical because
they are randomized and therefore any difference
in the measured outcome is due to the
intervention

7. Critical appraisal of RCTs
 Factors to look for:
 sample size (power calculation);
 Eligibility criteria
 Base line characteristics
 allocation (randomization, stratification, confounders);
 blinding;
 follow up of participants (intention to treat);
 data collection (bias);
 presentation of results (clear, precise);
 applicability to local population.

8. Sample size calculation (Power
calculation)
 A trial should be big enough to have a high chance of detecting a
worthwhile effect if it exists.
 Statisticians can work out before the trial begins how large the
sample size should be in order to have a good chance of detecting
a true difference between the intervention and control groups
PopulationPopulation SampleSample

9. Eligibility criteria
 This criterion is satisfied if the report describes
the source of subjects and a list of criteria
used to determine who was eligible to
participate in the study.
 inclusion and exclusion criteria should be
relevant for the study method and question —
i.e., a study shouldn’t exclude people with
certain weight or height, if this is not relevant
to the study outcomes or question posed

10. Baseline characteristics
 Both the control group and
the intervention group should
be broadly similar in factors
like age, sex distribution and
level of illness.

12. Randomization

14. Blinding
 Keep one or more of the
people involved in the trial
unaware of the intervention
that is being evaluated
 Purpose: decrease risk of bias
 Blinding can be implemented in
at least 6 levels in RCT
 Participants
 Investigators who administer
interventions
 Investigators taking care of the
participants
 Investigators assessing the
outcomes
 Data analyst
 Investigators who write results of
the trial

15. Blinding

16. Intention to treat
 Some participants would not complete
the study because of misdiagnosis, non-
compliance, or withdrawal
 When such patients excluded from
analysis, we can no longer be sure that
important prognostic factors in the 2
groups are similar which lead to potential
bias
 To reduce this bias, results should be
analyzed on an ‘intention to treat’ basis

17. Intention to treat

18. Out comes
 This requires your judgment —
look at what outcomes were
reported, and how these
answer the question posed
by the study

19. applicability to local population.
 Is our patient so different from those in the study that the results
can’t apply?
 Is the treatment feasible in our setting?
 What are our patient’s potential benefits and harms from the
therapy?
 What are the patient’s values and expectations for both the
outcome we are trying to prevent and the treatment we are
offering?
PopulationPopulation

20. Advantages & disadvantages of critical
appraisal and RCT
 Advantages
 systematic way of assessing validity, results & usefulness of research
 contributes to improving practice (quality)
 encourages objective assessment of information
 not difficult to develop skills
 Tries to disprove the null hypothesis
 Tries to eradicate bias because the two groups are identical
 Disadvantages
 time consuming
 not always any easy answers or what you hoped to find
 dispiriting if ‘good’ evidence is lacking i.e. little / poor research done

23. Summary
 Relationship between PICO & study design is important
 Assessing quality of studies & justification of outcomes is
cornerstone of critical appraisal
 Use of checklists provides consistency of approach & ensures
relevant questions are asked.
 Different study designs need different questions to be asked
so we use different critical appraisal checklists

24. Reference
 The PEDro scale is based on the Delphi list developed by Verhagen
and colleagues at the Department of Epidemiology, University of
Maastricht ( Verhagen AP et al (1998)
 2010; 90:880-894.PHYS THER. Fitzgerald Anthony M. DiGioia III,
Timothy J. Levison and G. Kelley Sara R. Piva, Alexandra B. Gil,
Gustavo J.M. Almeida, Randomized Clinical Trial Function for
Patients With Total Knee Arthroplasty: A A Balance Exercise Program
Appears to Improve
 Appraisal of an RCT using a critical appraisal checklist Spink MJ, et
al.
 Critical appraisal of a journal article
 CASP www.sph.nhs.uk/what-we-do/public-health-
workforce/resources;

25. Thank u