all self explanatary in document
Assignment Aim The aim of this assignment is for you to understand the process of appraising a research article. You will be reading three articles, determine their research question, their study design, and level of evidence. The level of evidence helps you make an assessment about the strength of the study. You will then critically analyse these articles to determine their quality, validity (possible sources of bias), and then interpret the results. Resources 1. Centre for Evidence-based Medicine at the University of oxford website http://www.cebm.net/ 2. CEBM levels of evidence https://www.cebm.net/2016/05/ocebm-levels-of-evidence/ 3. CEBM Introduction to study design https://www.cebm.net/wp-content/uploads/2014/06/CEBM-study-design-april-20131.pdf 4. CEBM Critical Appraisal for Diagnostic studies https://www.cebm.net/wp-content/uploads/2014/04/diagnostic-study-appraisal-worksheet.pdf 5. International Centre for Allied Health Evidence (iCAHE) Critical Appraisal Tools http://www.unisa.edu.au/Research/Sansom-Institute-for-Health-Research/Research/Allied-Health-Evidence/Resources/CAT/ 6. Critical Appraisal Skills Programme (CASP): http://www.casp-uk.net/ 7. Milanese, S & Grimmer, K 2015, 'Evidence‐based practice in sonography – the basics', Sonography, vol. 2, no. 3, pp. 53-56. 8. Milanese, S, Thoirs, K & Grimmer, K 2015, 'Evidence-based practice in sonography - making sense of diagnostic accuracy studies', Sonography, vol. 2, no. 4, pp. 69-73. Tasks Read through the material below, and work your way through the questions that are outlined in red. You may find the resources listed above useful when going through the questions.The three articles that you will be working with are: Fratelli, N, Scioscia, M, Bassi, E, Musola, M, Minelli, L & Trivella, G 2013, ‘Transvaginal Sonography for Preoperative Assessment of Deep Endometriosis’, J Clin Ultrasound, vol. 41, no. 2, pp. 69-75. Larson, A-K, Svalenius, EC, Lundqvist, A & Dykes, A-K 2010, ‘Parents’ experiences of an abnormal ultrasound examination – vacillating between emotional confusion and sense of reality’, Reproductive Health, vol. 7, no. 10, accessed online September 2018, http://www.reproductive-health-journal.com/content/7/1/10 Newnham, J, Evans, S, Michael, C, Stanley, F & Landau, L 1993, 'Effects of frequent ultrasound during pregnancy: a randomised controlled trial', The Lancet, vol. 342, no. 8876, pp. 887-891. Complete the answers where indicated with yellow highlighting. Please use the marks allocated to each question as a guide to the amount of detail required in your response. Verbs highlighted in green indicate the type of response required. This is good practice for the exams you will have throughout the program. Study Designs The following is a brief guide to different types of studies. All these study designs all have similar components · A defined population (P) from which groups of subjects are studied · Outcomes (O) that are measured And for experimental and analytic observational studies: · Interventions (I) or exposures (E) that are applied to different groups of subjects The figure below shows a tree of most basic study designs. The two main subgroups of study designs are descriptive or analytic. Analytic studies are further grouped into experimental or observational. Tree of different types of studies A descriptive study does not try to quantify the relationship but tries to give us a picture of what is happening in a population, e.g., the prevalence, incidence, or experience of a group. Types of descriptive studies include case reports, case-series, qualitative studies and surveys (cross-sectional) studies, which measure the frequency of several factors, and hence the size of the problem. They may sometimes also include analytic work. An analytic study attempts to quantify the relationship between two factors, that is, the effect of an intervention (I) or exposure (E) on an outcome (O). To quantify the effect we will need to know the rate of outcomes in a comparison (C) group as well as the intervention or exposed group. Whether the researcher actively changes a factor or imposes uses an intervention determines whether the study is considered to be observational (passive involvement of researcher), or experimental (active involvement of researcher). In experimental studies, the researcher manipulates the exposure, that is he or she allocates subjects to the intervention or exposure group. Experimental studies, or randomised controlled trials (RCTs), are similar to experiments in other areas of science. That is, subjects are allocated to two or more groups to receive an intervention or exposure and then followed up under carefully controlled conditions. Such controlled trials, particularly if randomised and blinded, have the potential to control for most of the biases that can occur in scientific studies but whether this actually occurs depends on the quality of the study design and implementation. In analytic observational studies, the researcher simply measures the exposure or treatments of the groups. Analytical observational studies include case control studies, cohort studies and some population (cross-sectional) studies. These studies all include matched groups of subjects and assess associations between exposures and outcomes. Observational studies investigate and record exposures (such as interventions or risk factors) and observe outcomes (such as disease) as they occur. Such studies may be purely descriptive or more analytical. Studies can incorporate several design elements. For example, the control arm of a randomised trial may also be used as a cohort study; and the baseline measures of a cohort study may be used as a cross-sectional study. The type of study can generally be worked out by looking at three issues (as per the Tree of design above); Q1 What is the aim of the study? Q2 if analytic, was the intervention randomly allocated? Q3 When were the outcomes determined? The following is a description of some of the common types of studies. 1. Randomised controlled trial: An experimental comparison study in which participants are allocated to treatment/intervention or control/placebo groups using a random mechanism (see randomisation). Best for study the effect of an intervention. Advantages: · unbiased distribution of confounders; · blinding more likely; · randomisation facilitates statistical analysis. Disadvantages: · expensive: time and money; · volunteer bias; · ethically problematic at times. 2. Cross-over design: A controlled trial where each study participant has both therapies, e.g, is randomised to treatment A first, at the crossover point they then start treatment B. Only relevant if the outcome is reversible with time, eg. symptoms. Advantages: · all subjects serve as own controls and error variance is reduced thus reducing sample size needed; · all subjects receive treatment (at least some of the time); · statistical tests assuming randomisation can be used; · blinding can be maintained. Disadvantages: · all subjects receive placebo or alternative treatment at some point; · washout period lengthy or unknown; · cannot be used for treatments with permanent effects 3. Cohort study: Data are obtained from groups who have been exposed, or not exposed, to the new technology or factor of interest (eg from databases). No allocation of exposure is made by the researcher. Best for study the effect of predictive risk factors on an outcome. Advantages: · ethically safe; · subjects can be matched; · can establish timing and directionality of events; · eligibility criteria and outcome assessments can be standardised; · administratively easier and cheaper than RCT. Disadvantages: · controls may be difficult to identify; · exposure may be linked to a hidden confounder; · blinding is difficult; · randomisation not present; · for rare disease, large sample sizes or long follow-up necessary. 4. Case control study: Patients with a certain outcome or disease and an appropriate group of controls without the outcome or disease are selected (usually with careful consideration of appropriate choice of controls, matching, etc) and then information is obtained on whether the subjects have been exposed to the factor under investigation. Advantages: · quick and cheap; · only feasible method for very rare disorders or those with long lag between exposure and outcome; · fewer subjects needed than cross-sectional studies. Disadvantages: · reliance on recall or records to determine exposure status; · confounders; · selection of control groups is difficult; · potential bias: recall, selection. 5. Cross-sectional survey: A study that examines the relationship between diseases (or other health-related characteristics) and other variables of interest as they exist in a defined population at one particular time (ie exposure and outcomes are both measured at the same time). Best for quantifying the prevalence of a disease or risk factor, and for quantifying the accuracy of a diagnostic test. Advantages: · cheap and simple; · ethically safe. Disadvantages: · establishes association at most, not causality; · recall bias susceptibility; · confounders may be unequally distributed; · Neyman bias; · group sizes may be unequal. RADY 5024 Professional Issues for SonographersSP2 2020 Evidence Based Practice assignment 2 Q1. Fill in the table below for each of the three studies. A short descriptor is required for the PICO columns. Use N/A if the study does not describe any of the factors – PICO does not always apply well in a qualitative context. [15 marks] – 1 mark per box. Study name Aim of study Population Intervention or Exposure Comparator Outcome(s). NB: this is not the results – please don’t state what the findings were. Effects of frequent ultrasound during pregnancy: a randomised controlled trial Newnham et al 1993 Transvaginal Sonography for Preoperative Assessment of Deep Endometriosis. Fratelli et al 2013 Parents’ experiences of an abnormal ultrasound examination – vacillating between emotional confusion and sense of reality. Larsson et al 2010 Q2. In which study was the intervention randomly allocated? [1 mark] Answer: Q3. It is important to be able to identify the design of a particular study. The range of designs are introduced via this link: http://www.cebm.net/wp-content/uploads/2014/06/CEBM-study-design-april-2013.pdf Using this flow chart, what kind of study is that presented by Larsson et al, 2010? [1 mark] Answer: Q4. Looking at the evidence for adopting a new protocol will play a vital part in your role as a sonographer. One aspect of critically appraising the literature that you find is determining how strong the evidence is which is being presented. Task: Read through the CEBM Levels of Evidence Introductory Document, and download the Levels of Evidence Document: https://www.cebm.net/2016/05/ocebm-levels-of-evidence/ Consider the Newnham et al (1993) and Fratelli et al (2013) papers. Read down the first (shaded) column of the Levels of Evidence table. Q4a. Identify which research question type aligns with each of the papers [2 marks]: Answer: Newnham et al (1993): Fratelli et al (2013): Now that you have identified the question type, follow along the corresponding row on the CEBM table for each paper, and find the type of study. Once you have located this, refer to the heading of that column – this gives you the level of evidence ranking for each study. Q4b. What are the levels of evidence for each of the papers? [2 marks] Answer: Newnham et al (1993): Fratelli