Module 1 Unit 2 PDF

2 Reading the Medical Literature 2.1 Common Study Designs 2.2 Critique of a Scientific Publication Overview This unit will show you how to determine the appropriate use...

2 Reading the Medical Literature 2.1 Common Study Designs 2.2 Critique of a Scientific Publication Overview This unit will show you how to determine the appropriate use of study designs based on the research question and evaluate the methodological quality of the scientific publication. It will also guide you in the preparation and presentation of a critique of scientific publications. Learning Objectives By the end of this Unit you will be able to: 1. Evaluate the methodological quality of a scientific publication; 2. Identify potential sources of bias and confounding in a scientific publication; 3. Reconcile the strengths and weaknesses of a scientific publication. Session 2.1: Common Study Designs Session 2.2: The Critique of a Scientific Publication HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 9  Readings and Resources Required Readings Holmes, M. & Cockcroft, P. (2003). Handbook of Evidence-Based Veterinary Medicine. Blackwell Publishing Ltd. Chap 5-6. How to read a Paper: The basics of evidence-based medicine. Trisha Greenhalgh, Blackwell Publishing, BMJ (2010). Chap 3-4 Other Resources CONSORT 2020 https://www.equator-network.org/reporting-guidelines/consort/ von Elm E, Altman DG, Egger M, Pocock SJ, G0tzsche PC, Vandenbroucke JP; STROBE Initiative. (2008). The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE)statement: guidelines for reporting observational studies. J Clin Epidemiol. 2008 Apr;61(4):344-9. PMID: 18313558 http://www.strobe-statement.org/strobe-publications/ 10 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Session 2.1 Common Study Designs Introduction It is important that the study design aligns with the research question because this is fundamental to the utility of the study. Choosing the appropriate study design will help to answer the research question without wasting valuable and scarce resources. During your appraisal of the literature, you should be able to comment on whether or not the most appropriate study design was selected for the research question. This course will focus on quantitative studies. Therefore, you should know about various study designs especially the four most commonly used in epidemiological studies- cross-sectional/survey, case-control, cohort and clinical trials. The first step is to review the background and determine the type of research question (Table 2.1.1) after which you will evaluate whether the appropriate study design was selected (Table 2.1.2). Table 2.1: Table 2.1.1: Classification/Type of healthcare research questions. Question Classification/Type How can this problem be prevented? Prevention Will detecting this problem early, before symptoms, make Screening a difference in the individuals' health? How good is this test at detecting this problem? Diagnostic Accuracy What is the likely outcome of this problem? Prognosis What proportion of the population is newly diagnosed Incidence with this problem each year? What proportion of the population is currently living with Prevalence this problem? What causes this problem? Etiology What should be done to treat this problem? Therapy Will there be any negative effects (of an intervention)? Harm HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 11  Table 2.2: Table 2.1.2: Summarizing the study design appropriate for the type of research question Question (TYPE) Best Evidence What is the burden of this disease? Surveys, Cross sectional studies (PREVALENCE) How many new cases are occurring? Cohort study (INCIDENCE) What causes this problem? (ETIOLOGY) Case Control Study, Cohort, Clinical Trial How can this problem be prevented? Clinical Trials (PREVENTION) Will detecting this problem early, Clinical Trials before symptoms, make a difference? (SCREENING) What should be done to treat this problem? Clinical Trials (THERAPY) Study Designs Cross Sectional Studies/Surveys A cross-sectional study examines the relationships between health outcomes and other characteristics of a defined population at a particular point in time. These studies may be observational or analytical and the exposure and outcomes are assessed simultaneously. (see Figure 2.1). They provide the prevalence of disease, exposure and/or risk factors. They are also useful for improving disease awareness and for the assessment and planning of health interventions. 12 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Figure 2.1: Cross-sectional Study Design Source: https://study.com/cimages/multimages/16/cross_sectional_research_study.png Case Control Studies For these analytical studies, a comparison is made between a group of persons (cases) who are selected on the basis of their disease (outcome) status and a group of persons without the outcome (controls). This study looks back in time to see how the risk factors/exposures of the two groups differ based on disease status (see Figure 2.2). Multiple exposures can be studied at the same time. In the case-control study, it is important that the case is clearly defined. Depending on the outcome, time and resources then the definition may be based on clinical findings, laboratory or other investigations or a combination of these. Controls should not have the outcome of Interest or any condition that could result in unusually low or high prevalence of the exposure. They should ideally be selected from the same population as the cases. Case-control studies are: useful for investigating outbreaks conducted quickly Cost effective Suitable for rare diseases HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 13  These studies, however, cannot be used to establish temporal relationships conducted retrospectively and are often prone to bias depending on how cases and controls are identified and the methods used to collect information about exposure. Figure 2.2: Case Control Study Design Source: http://pathbliss.com/wp-content/uploads/2018/04/Case-control-cover.png Cohort Studies In these analytical studies, a group of persons are classified (or sometimes selected) according to exposure to a risk factor and are then followed forward in time until the development of a disease or an outcome of interest (see Figure 2.3). At the start of the study, persons are free of the outcome and should be at risk for the outcome being assessed. Usually, there is a comparison of the incidence rate between groups that differ in exposure levels. They are effective for assessing multiple exposures and outcomes and for looking at rare exposures but NOT rare outcomes. 14 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Figure 2.3: Cohort Study Designs Source: https://i.pinimg.com/originals/98/e0/da/98e0dabab15dd59494c10f4ac7830c91.jpg Randomized Clinical Trials (RCTs) Clinical trials are experimental study designs in which the exposure status of the participant is determined by the investigator. The Randomized Control Clinical Trial (RCT) is the best study to use when trying to establish a relationship between cause and effect. Each participant Is carefully selected by pre-specified inclusion criteria and randomly allocated to the intervention/treatment group or to the control/placebo group(s). The groups are then followed up throughout the study time to determine the effect of the intervention (see Figure 2.4). There should be clinical equipoise (i.e. there must be some degree of uncertainty about the benefits or harms that may result from this particular intervention before undertaking this type of study). This is critical as participants may be at risk or prevented from receiving beneficial treatment. A properly conducted clinical trial can provide strong evidence of a causal relationship between exposure and outcome and can control for confounding factors that might explain differences in outcome between groups. HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 15  Figure 2.4: Randomized Controlled Clinical Trial Study Design Source: http://slideplayer.com/slide/5712569/18/images/32/Randomized+controlled+trial+design.jpg Assessing the Appropriateness It is important to determine If the appropriate study design was selected to answer the research question as this will affect your appraisal. The criteria for appraisal varies with the type of study design and there are several checklists available to assist and guide you in this process. The Strengthening and the Reporting of Observational studies in Epidemiology (STROBE) checklist is used for observational studies while the Consolidated Standards of Reporting Trials (CONSORT) is used for the reporting of randomized control trials. Please access the hyperlinks below to view the checklists available. 16 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Readings How to read a Paper: The basics of evidence-based medicine. Trisha Greenhalgh, Blackwell Publishing, BMJ (2010). Chap 3 CONSORT 2010: https://www.equator-network.org/reporting- guidelines/consort/ Vandenbroucke JP, von Elm E, Altman DG, Gøtzsche PC, Mulrow CD, Pocock SJ,Poole C, Schlesselman JJ, Egger M; STROBE Initiative. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. Epidemiology. 2007 Nov;18(6):805-35. PMID: 18049195 https://www.sciencedirect.com/science/article/pii/S174391911400213 1?via%3Dihub : https://pubmed.ncbi.nlm.nih.gov/8672166/ HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 17  Reflective-reflexive Practice Session 2.1 Summary This session introduced you to four commonly used epidemiological study designs. After identifying the study design in the scientific paper, you should then use the appropriate checklist to determine if the most suitable study design was used to answer the research question. This is a fundamental part of your critique. 18 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Session 2.2 The Critique of a Scientific Publication Introduction Critical appraisal is the assessment of evidence by systematically reviewing its relevance, validity and results to specific situations (1). Critical appraisal is the balanced assessment of the strengths and weaknesses of a scientific paper through evaluation of the value, methodology, results, ethical considerations and completeness of reporting. Format of the Critique After the selection and critical appraisal of your paper, you will need to present your critique. The use of a consistent format will help to ensure a systematic appraisal and improve efficiency and thoroughness. The use of this 10-step guideline will allow you to increase your efficiency in the evaluation of the validity of the study and improve your confidence in writing and presenting a critique. 1. Statement of Problem and Purpose 2. Review of the literature 3. Search Strategy 4. Study Design 5. Research question and relevance 6. Description of the methodology 7. Findings of Critical Appraisal questions of Validity 8. Summary the primary results 9. Assessment of external validity 10. Conclusion HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 19  Statement of Problem and Purpose Begin with a brief explanation of the purpose/problem of the research paper. What is the relevance to you? What is the significance of the problem identified, if any? This is important for better engagement of your audience. Review of the Literature The introduction and background presented by the authors should be reviewed for concepts, definitions, theoretical framework, and references. Are the references pertinent or inconsequential? Search Strategy Give a brief description of the search strategy that was used to find and select the article. This should include the databases and search terms as well as the criteria for the final selection. Study Design The study design should be explicitly described and its appropriateness should be declared. This should include ethical considerations and informed consent where applicable. Research Question and Relevance This is a critical component of the study. A well-developed question should contain all the elements of the PICO (population, intervention/exposure, control/comparison and outcome). You should also state the context or importance of the question. Description of Methodology The method should provide more detail on the elements of the research question specifically on how the exposure and outcome of interest was measured, participants were selected, confounding factors were measured Also included here should be a description of approaches that were used to prevent and evaluate any systematic error (bias). The approach to analysis of the data may also be presented. Findings of Critical Appraisal Questions of Validity Utilizing an appropriate tool for evaluation of the study design, answer the applicable questions and provide your evaluation of the study methods, including the role of potential bias or confounding on study conclusions. 20 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Summary of Primary Results Summarize the results in relation to the research question primarily and report secondary results if they are significant or relevant. You should mention any significant findings in the figures or tables. Assessment of external validity The external validity of the study should be assessed to determine the applicability to your practice or setting. Are the findings completely impracticable or are there adjustments that are possible to overcome the differences? Conclusion State your conclusion about the study findings and the resolution to the research question. Provide any recommendations and implications of the study. Readings How to read a Paper: The basics of evidence-based medicine. Trisha Greenhalgh, Blackwell Publishing, BMJ (2010). Chap 4. Elwood, J.M. (2017). Critical Appraisal of Epidemiological Studies and Clinical Trials. Oxford University Press. Chap 12-17. ► https://www.ucl.ac.uk/child- health/sites/child_health/files/library_critical_appraisal_handout.pdf ► https://blogs.kent.ac.uk/chss-library-guide/critical-appraisal/critical- appraisal-resources/ HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 21  LEARNING ACTIVITY 2.3 Critical Appraisal of a Scientific Paper For this activity, you will be given a journal article for critical appraisal. Use the questions below as a guide to prepare a critique of the article for a 10-minute presentation. Critical Appraisal discussion points 1. What was the purpose of this study? 2. Was this study design able to provide an answer this question? 3. Who did they study (Population)? 4. How was the sample selected? What was the refusal rate like? 5. What were the exposure and outcome variables? Was there a comparison group? 6. What were the main results of this paper? 7. What were the main conclusions of this paper? 8. What are some strengths of this study? 9. What are some potential limitations of the study? Consider the following areas: measurement of exposure, determination of outcomes, selection of subjects, statistical analysis 10. What are some potential hypotheses you might want to explore from this study? 11. How could this study have been improved? 22 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  Play Video Reading A Paper In this video, you will find some helpful hints that will assist you in the critical appraisal of your paper. ► https://www.youtube.com/watch?v=eSEP2T-xz8g&t=181s Quiz Session 2.2 Summary This session introduced the concept of critical appraisal of the scientific literature. The approach to critical reading and preparation of the critique of a scientific paper were highlighted using recognized formats. HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 23  Unit 2 Summary In unit 2, a review of the common study designs was done to enable you to better utilize the appraisal tools for observational and experimental studies. You should also be able to read and critically appraise a scientific paper. Additionally, you should be able to prepare a 10-minute presentation to share your findings with your colleagues and other audience. Module 1 Wrap Up At the end of this module, we expect you have been able to identify appropriate databases for scientific literature and apply this to your scientific reading and writing. The resources, readings and activities provided will help to improve your competence in reading and critiquing a scientific paper or publication. You should be able to present your findings in a succinct manner for various target audiences. Critical appraisal of other scientific writings will improve your formulation of your own manuscript and thus prepare you for Module 2. 24 HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1  References Chambers R, 'Clinical Effectiveness Made Easy', Oxford: Radcliffe Medical Press. How to read a Paper: The basics of evidence-based medicine. Trisha Greenhalgh, Blackwell Publishing, BMJ (2010). Omair, A. (2015). Selecting the appropriate study design for your research: Descriptive study designs. Journal of Health Specialties Vol 3 Issue 3. Retrieved from https://www.researchgate.net/publication/281223251_Selecting_the_appropriate_stu dy_design_for_your_research_Descriptive_study_designs HERP5104 Critical Evaluation of the Medical Literature & Writing Scientific Manuscripts – MODULE 1 25