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Critical appraisal presentation by mohamed taha 2

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Cairo University
Cairo University

This document discusses how to critically appraise a research article. It provides 10 questions to ask when appraising an article, including whether the study question is relevant, if the study design was appropriate, and if the data supports the conclusions. As an example, it summarizes a study that examined the relationship between serum cholesterol levels and exposure to violence in suicide attempters. The study addressed relevant questions, utilized an appropriate cohort study design, and its conclusions were reasonably supported by the collected data.

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Critical Appraisal Presented by How to critically MOHAMED TAHA appraise MOHAMED an Assistant lecturer of psychiatry article? Faculty of Medicine - Beni Suef University
WHAT IS CRITICAL APPRAISAL?? Critical appraisal is a systematic process used to identify the strengths and weaknesses of a research article in order to assess the usefulness and validity of research findings. The most important components of a critical appraisal are an evaluation of the appropriateness of the study design for the research question and a careful assessment of the key methodological features of this design.
Selection and critical appraisal of research literature 10 QUESTIONS TO ASK WHEN CRITICALLY APPRAISING A RESEARCH ARTICLE: 1-Is the study question relevant? 2-Does the study add anything new? 3-What type of research question is being asked? 4-Was the study design appropriate for the research question?
TEN QUESTIONS TO ASK WHEN CRITICALLY APPRAISING A RESEARCH ARTICLE: Cont. 5. Did the study methods address the most important sources of bias? 6. Was the study performed according to the original protocol? 7. Does the study test a stated hypothesis? 8. Were the statistical analyses performed correctly? 9. Do the data justify the conclusions? 10. Are there any conflicts of interest?
Critical appraisal presentation by mohamed taha 2
1- Is the study question relevant? Even if a study is of the highest methodological design it is of little value unless it addresses an important topic and adds to what is already known about It. This is based on subjective opinion, as what might be crucial to some will be irrelevant to others.
1- Is the study question relevant? Cont. In this study: The question was to determine The role of serum cholesterol in the cycle of violence. And to investigate association between exposure to violence during childhood And used adult violence in suicide attempters with low and high serum cholesterol levels. Which is considered relevant and crucial to our field of work.
2-Does the study add anything new? Research papers that make a substantial new contribution to knowledge are a relative rarity. For example, a study might increase confidence in the validity of previous research by replicating its findings. Or might enhance the ability to generalize a study by extending the original research findings to a new population of patients.
2-Does the study add anything new? This study discussed a new subject ,role of serum cholesterol in the cycle of violence . As was found that a significant correlation between exposure to violence as a child and expression of violence as an adult(i.e. cycle of violence),only in the group with cholesterol levels below the median. Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised Individuals & increased the confidence in the validity of previous research by replicating its findings e.g. The link between cholesterol and violence is hypothesised to be Mainly mediated through alteration of serotonergic activity. Low Cholesterol is related to low serotonin and, in turn, linked to violence, suicidal behaviour and impulsivity ( Wallnerand Machatschke, 2009).
3-What type of research question is being asked? The most fundamental task of critical appraisal is to identify the specific research question; which will determine the optimal study design.
3-What type of research question is being asked? Cont. A well-developed research question usually identifies three components: 1-The group of patients. 2-The studied parameter (e.g. a therapy, clinical intervention, or a risk factor). 3-The outcomes of interest.
3-What type of research question is being asked? Cont. In this study the research question identified the three important components: 1-The group of patients: 81 patients with a recent suicide attempt . 2-The studied parameter : Serum cholesterol level, the exposure to and expression of interpersonal violence as a child and as an adult . 3-The outcomes of interest: Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised Individuals.
4-Was the study design appropriate for the research question?
-Studies that answer questions about effectiveness have a well-established hierarchy of study designs based on the degree to which the design protects against bias. - RCTsprovide the strongest evidence followed by non RCT, cohort studies, casecontrol studies & other observational study designs .
4-Was the study design appropriate for the research question? Cont. In this study : This study design is considered appropriate for the research question.
4-Was the study design appropriate for the research question? Cont. Cohort, or longitudinal, studies involve following up two or more groups of patients to observe who develops the outcome of interest. Prospective cohort studies have been likened to natural experiments, as outcomes are measured in large groups of individuals over extended periods of time in the real world. Cohort studies can also be performed retrospectively; such studies usually involve identifying a group of patients and following up their progress by examining records that have been collected routinely or for another purpose, such as medical data, death registry records and hospital admission databases.
Critical appraisal presentation by mohamed taha 2
Advantages of cohort studies The temporal dimension, where by exposure is seen to occur before outcome, gives some indication of causality Can be used to study more than one outcome Good for the study of rare exposures Can measure the change in exposure and outcome over time Incidence of outcome can be measured
Disadvantages of cohort studies Costly (less so for retrospective) and may take a long time, particularly where onset of the outcome measure can occur both early and late on in life Require accurate records for retrospective studies When studying rare outcomes, a very large sample size is required Prone to dropout Changes in aetiology of disease over time may be hard to disentangle from changes observed as age increases Selection bias: a difference in incidence of the outcome of interest, between those who participated and those who did not, would give biased results
5. Did the study methods address the most important potential sources of bias? In epidemiological terms: The presence of bias does not imply a preconception on the part of the researcher, but rather means that the results of a study have deviated from the truth. Bias can be attributed to chance (e.g. a random error) or to the study methods (systematic bias). Random error does not influence the results but it will affect the precision of the study.
5. Did the study methods address the most important potential sources of bias? cont. Key methodological points to consider in the appraisal of a Cohort, study . Is the study prospective or retrospective? Is the cohort representative of a defined group or population?
Key methodological points to consider in the appraisal of a cross-sectional study. Cont. Were there important losses to follow-up? Were all important confounding factors identified?
5. Did the study methods address the most important potential sources of bias? Cont. In this study 1- Is the study prospective or retrospective? the study is retrospective . 2-Is the cohort representative of a defined group or population? Yes, study participants (81 patients )were recruited among patients having recently com-mitted a suicide attempt and having their clinical follow-up at the Karolinska University Hospital..
5. Did the study methods address the most important potential sources of bias? Cont. 3-Were all important confounding factors identified? Not really; Because of a small sample size ,leading to a limitation of the amount of independent variables that could be used and Relatively large age span might also some what confound the results. 4-Were there important losses to follow-up? there are no important losses to follow up.
6. Was the study performed according to the original protocol? One of the most common problems encountered in clinical research is the failure to recruit the planned number of participants written in the protocol. Other differences to the protocol include: -changes to the inclusion and exclusion criteria, - or variations in the provided interventions etc...
6. Was the study performed according to the original protocol? In this study: The study protocols (Dnr 93-211) were Approved by the Regional Ethical Review Board in Stockholm, and all patients gave their written informed consent before inclusion in the study.
7. Does the study test a stated hypothesis? A hypothesis is a clear statement of what the investigators expect the study to find and is central to any research as it states the research question in a form that can be tested and refuted. In this study There was a clear hypothesis stated.
8. Were the statistical analyses performed correctly? Assessing the appropriateness of statistical analyses can be difficult for non-statisticians. Yet, research articles should include a segment within their 'Method' section that explains the tools used in the statistical analysis and the rationale for this approach. In this study: Group differences were computed with one-way ANOVA . Tests of parametric correlations were performed using Pearson0`s and non-parametric correlations using Spearman`s.
9. Do the data justify the conclusions? The next consideration is whether the conclusions presented are reasonable on the basis of the accumulated data. Sometimes an overemphasis is placed on statistically significant findings that invoke differences that are too small to be of clinical value; Alternatively, some researchers might dismiss important differences between groups that are not statistically significant, often because sample sizes were small.
9. Do the data justify the conclusions? In this study The conclusions that the authors presented were reasonable on the basis of the accumulated data: There is a significant correlation between expo-sure to violence as a child and expression of violence as an adult(i.e. cycle of violence),only in the group with cholesterol levels below the median. Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised individuals.
10. Are there any conflicts of interest? Conflicts of interest occur when personal factors have the potential to influence professional roles . In the process of critically appraising a research article, one important step is to check for a declaration about the source of funding for the study.
10. Are there any conflicts of interest? A main mechanism for dealing with potential conflicts of interest is open disclosure. In this study: There was no declaration about the source of funding.
Critical appraisal presentation by mohamed taha 2

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Critical appraisal presentation by mohamed taha 2

  • 1. Critical Appraisal Presented by How to critically MOHAMED TAHA appraise MOHAMED an Assistant lecturer of psychiatry article? Faculty of Medicine - Beni Suef University
  • 2. WHAT IS CRITICAL APPRAISAL?? Critical appraisal is a systematic process used to identify the strengths and weaknesses of a research article in order to assess the usefulness and validity of research findings. The most important components of a critical appraisal are an evaluation of the appropriateness of the study design for the research question and a careful assessment of the key methodological features of this design.
  • 3. Selection and critical appraisal of research literature 10 QUESTIONS TO ASK WHEN CRITICALLY APPRAISING A RESEARCH ARTICLE: 1-Is the study question relevant? 2-Does the study add anything new? 3-What type of research question is being asked? 4-Was the study design appropriate for the research question?
  • 4. TEN QUESTIONS TO ASK WHEN CRITICALLY APPRAISING A RESEARCH ARTICLE: Cont. 5. Did the study methods address the most important sources of bias? 6. Was the study performed according to the original protocol? 7. Does the study test a stated hypothesis? 8. Were the statistical analyses performed correctly? 9. Do the data justify the conclusions? 10. Are there any conflicts of interest?
  • 6. 1- Is the study question relevant? Even if a study is of the highest methodological design it is of little value unless it addresses an important topic and adds to what is already known about It. This is based on subjective opinion, as what might be crucial to some will be irrelevant to others.
  • 7. 1- Is the study question relevant? Cont. In this study: The question was to determine The role of serum cholesterol in the cycle of violence. And to investigate association between exposure to violence during childhood And used adult violence in suicide attempters with low and high serum cholesterol levels. Which is considered relevant and crucial to our field of work.
  • 8. 2-Does the study add anything new? Research papers that make a substantial new contribution to knowledge are a relative rarity. For example, a study might increase confidence in the validity of previous research by replicating its findings. Or might enhance the ability to generalize a study by extending the original research findings to a new population of patients.
  • 9. 2-Does the study add anything new? This study discussed a new subject ,role of serum cholesterol in the cycle of violence . As was found that a significant correlation between exposure to violence as a child and expression of violence as an adult(i.e. cycle of violence),only in the group with cholesterol levels below the median. Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised Individuals & increased the confidence in the validity of previous research by replicating its findings e.g. The link between cholesterol and violence is hypothesised to be Mainly mediated through alteration of serotonergic activity. Low Cholesterol is related to low serotonin and, in turn, linked to violence, suicidal behaviour and impulsivity ( Wallnerand Machatschke, 2009).
  • 10. 3-What type of research question is being asked? The most fundamental task of critical appraisal is to identify the specific research question; which will determine the optimal study design.
  • 11. 3-What type of research question is being asked? Cont. A well-developed research question usually identifies three components: 1-The group of patients. 2-The studied parameter (e.g. a therapy, clinical intervention, or a risk factor). 3-The outcomes of interest.
  • 12. 3-What type of research question is being asked? Cont. In this study the research question identified the three important components: 1-The group of patients: 81 patients with a recent suicide attempt . 2-The studied parameter : Serum cholesterol level, the exposure to and expression of interpersonal violence as a child and as an adult . 3-The outcomes of interest: Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised Individuals.
  • 13. 4-Was the study design appropriate for the research question?
  • 14. -Studies that answer questions about effectiveness have a well-established hierarchy of study designs based on the degree to which the design protects against bias. - RCTsprovide the strongest evidence followed by non RCT, cohort studies, casecontrol studies & other observational study designs .
  • 15. 4-Was the study design appropriate for the research question? Cont. In this study : This study design is considered appropriate for the research question.
  • 16. 4-Was the study design appropriate for the research question? Cont. Cohort, or longitudinal, studies involve following up two or more groups of patients to observe who develops the outcome of interest. Prospective cohort studies have been likened to natural experiments, as outcomes are measured in large groups of individuals over extended periods of time in the real world. Cohort studies can also be performed retrospectively; such studies usually involve identifying a group of patients and following up their progress by examining records that have been collected routinely or for another purpose, such as medical data, death registry records and hospital admission databases.
  • 18. Advantages of cohort studies The temporal dimension, where by exposure is seen to occur before outcome, gives some indication of causality Can be used to study more than one outcome Good for the study of rare exposures Can measure the change in exposure and outcome over time Incidence of outcome can be measured
  • 19. Disadvantages of cohort studies Costly (less so for retrospective) and may take a long time, particularly where onset of the outcome measure can occur both early and late on in life Require accurate records for retrospective studies When studying rare outcomes, a very large sample size is required Prone to dropout Changes in aetiology of disease over time may be hard to disentangle from changes observed as age increases Selection bias: a difference in incidence of the outcome of interest, between those who participated and those who did not, would give biased results
  • 20. 5. Did the study methods address the most important potential sources of bias? In epidemiological terms: The presence of bias does not imply a preconception on the part of the researcher, but rather means that the results of a study have deviated from the truth. Bias can be attributed to chance (e.g. a random error) or to the study methods (systematic bias). Random error does not influence the results but it will affect the precision of the study.
  • 21. 5. Did the study methods address the most important potential sources of bias? cont. Key methodological points to consider in the appraisal of a Cohort, study . Is the study prospective or retrospective? Is the cohort representative of a defined group or population?
  • 22. Key methodological points to consider in the appraisal of a cross-sectional study. Cont. Were there important losses to follow-up? Were all important confounding factors identified?
  • 23. 5. Did the study methods address the most important potential sources of bias? Cont. In this study 1- Is the study prospective or retrospective? the study is retrospective . 2-Is the cohort representative of a defined group or population? Yes, study participants (81 patients )were recruited among patients having recently com-mitted a suicide attempt and having their clinical follow-up at the Karolinska University Hospital..
  • 24. 5. Did the study methods address the most important potential sources of bias? Cont. 3-Were all important confounding factors identified? Not really; Because of a small sample size ,leading to a limitation of the amount of independent variables that could be used and Relatively large age span might also some what confound the results. 4-Were there important losses to follow-up? there are no important losses to follow up.
  • 25. 6. Was the study performed according to the original protocol? One of the most common problems encountered in clinical research is the failure to recruit the planned number of participants written in the protocol. Other differences to the protocol include: -changes to the inclusion and exclusion criteria, - or variations in the provided interventions etc...
  • 26. 6. Was the study performed according to the original protocol? In this study: The study protocols (Dnr 93-211) were Approved by the Regional Ethical Review Board in Stockholm, and all patients gave their written informed consent before inclusion in the study.
  • 27. 7. Does the study test a stated hypothesis? A hypothesis is a clear statement of what the investigators expect the study to find and is central to any research as it states the research question in a form that can be tested and refuted. In this study There was a clear hypothesis stated.
  • 28. 8. Were the statistical analyses performed correctly? Assessing the appropriateness of statistical analyses can be difficult for non-statisticians. Yet, research articles should include a segment within their 'Method' section that explains the tools used in the statistical analysis and the rationale for this approach. In this study: Group differences were computed with one-way ANOVA . Tests of parametric correlations were performed using Pearson0`s and non-parametric correlations using Spearman`s.
  • 29. 9. Do the data justify the conclusions? The next consideration is whether the conclusions presented are reasonable on the basis of the accumulated data. Sometimes an overemphasis is placed on statistically significant findings that invoke differences that are too small to be of clinical value; Alternatively, some researchers might dismiss important differences between groups that are not statistically significant, often because sample sizes were small.
  • 30. 9. Do the data justify the conclusions? In this study The conclusions that the authors presented were reasonable on the basis of the accumulated data: There is a significant correlation between expo-sure to violence as a child and expression of violence as an adult(i.e. cycle of violence),only in the group with cholesterol levels below the median. Serum cholesterol may thus modify the effect of the cycle of violence and might be of interest as a biomarker concerning risk of expression of violence in traumatised individuals.
  • 31. 10. Are there any conflicts of interest? Conflicts of interest occur when personal factors have the potential to influence professional roles . In the process of critically appraising a research article, one important step is to check for a declaration about the source of funding for the study.
  • 32. 10. Are there any conflicts of interest? A main mechanism for dealing with potential conflicts of interest is open disclosure. In this study: There was no declaration about the source of funding.

Editor's Notes

  • #9: validity refers to whether a study is able to scientifically answer the questions it is intended to answer
  • #28: It would go like: we expect to find that the severity of depression increase and that the academic achievement decrease as cellular phone dependence increases.