Dhiwahar ppt


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Dhiwahar ppt

  1. 1. Critical Appraisal of Randomized Controlled Trials Done By K.H. Dhiwahar . MPT (sports) P. Saba kannan raja .MPT (sports)
  2. 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.
  4. 4. Critical appraisal is an important element of evidence-based medicine. The five steps of evidence-based medicine are: Comparison outcomes
  5. 5. Hierarchy of evidence RCT
  6. 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. 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. 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. 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. 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.
  11. 11. Randomization
  12. 12. 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
  13. 13. Blinding
  14. 14. 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
  15. 15. Intention to treat
  16. 16. Out comes  This requires your judgment — look at what outcomes were reported, and how these answer the question posed by the study
  17. 17. 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
  18. 18. 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
  19. 19. 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
  20. 20. 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;
  21. 21. Thank u