Version 2 12/02/2020 Obesity and the risk of myocardial infarction in 27 000 participants from 52 countries: a case-control study You will be reading and interpreting a paper investigating obesity and the risk of myocardial infarction. In a future facilitation session you will be discussing with your colleagues what you have learnt from the paper and teaching the other half of the group, who are looking at a different paper, what you have found. Several of the concepts addressed here you will have come across in the Foundation of Medicine course, so you may find it helpful to go back over those notes. There are also some extra supporting materials you may find helpful listed at the end of the questions. The structured questions have been based on a series of appraisal articles in the BMJ (listed in the extra supporting materials). Learning objectives · Understand how to use a critical appraisal template in a structured way · Identify the design used in a study · Define the null hypothesis of a research question · Explain how to interpret odds ratios, 95% Confidence Intervals and p-values. The paper you will be reading and interpreting is: Yusuf et al. Obesity and the risk of myocardial infarction in 27 000 participants from 52 countries: a case-control study. Lancet. 2005;366(9497):1640-9. Read through the title, abstract and introduction of the paper Why was the study done, and what clinical question were the authors addressing? 1. What were the authors of this study aiming to find out? 2. What is the null hypothesis in this study? Page 1 of 6
Version 2 12/02/2020 Now read the methods 3. What type of study was done? Does this paper describe a primary study or a secondary study using pre-existing data (either routine or from older research)? 4. Why features of the design make this a case control study? 5. Why did the researches only include patients with their first heart attack and excluded those with a recurrent heart attack? 6. Was this design appropriate to the research? Other study types could have been considered to answer the research question. What are the pros and cons of these different types of studies when trying to address this research question? Make a table of the different epidemiological designs you covered in Foundations of Medicine and consider their pros and cons in relation to this hypothesis Other potential study type RCT Pros (for this research question) Page 2 of 6 Cons (for this research question)
Other potential study type Cohort study Case-control study Cross sectional survey Version 2 12/02/2020 Pros (for this research question) Cons (for this research question) How did they conduct the study? 7. How were subjects recruited into the study? Page 3 of 6