Clinical health issues
Answer questions 1-4 based on the following clinical scenario:
Asthma is a common medical condition caused by narrowing of the small air passages (breathing tubes) in the lungs. The narrowing happens because the air passages become swollen and inflamed. This
makes it difficult for air to get through and causes wheezing, coughing and problems with breathing. Approximately one in four children in Australia will have some symptoms of asthma during
childhood, but with the right medicine and interventions, nearly all children with asthma will be able to join in sport and lead active lives. There are many different things that can trigger or
start an asthma attack, including infection, exercise, changes in the weather, cigarette smoking, house dust mite, pollens and pets.
The Director of Paediatric Medicine department in an urban hospital in Melbourne notices that many children with asthma admitted to the Emergency Department (ED) for acute asthmatic attack re-
represent to the hospital in weeks following the initial admission to the ED. He wants to reduce re-admission rates of acute asthmatic attack at the hospital, and wonders if a short community
intervention in the form of a follow-up telephone call (to assess how the patients were feeling, and provide advice for community support such as avoidance of known allergies) might lead to
reductions in the number of re-admission due to acute asthmatic attack in children with asthma.
Q1 Write a focused clinical question for this particular problem that will help you organise a search of the clinical literature for an answer. [4 marks]
Q2 If you were to search Medline/PubMed/Web of science for original research on this question [8 marks]
(i) Describe what your search strategy would be. Be as specific with your response, and consider specific keywords, MeSH terms, and delimiters.
(ii) Explain your rationale for taking this approach and explain your reasoning.
(iii) Cite the best article from among those you find, using any referencing style of your choice.
Q3 What type of study design would best be able to address this question? Discuss why. [5 marks]
Q4 What information sources would you use to find an answer to questions such as the above? [5 marks]
(i) Name at least four (4) possible types or categories of information sources as you can that could be used to find relevant evidence.
(ii) Discuss at least three (3) types of information sources to demonstrate your awareness of the convenience, relevance and quality of common information sources in clinical practice.
Answer questions 5a-d based on the following information:
You have brought to the attention of the hospital medical services that a published trial reported reduced body weight in patients with morbid obesity who were treated with liraglutide, a glucagon-
like peptide-1 equivalent. You mentioned this published paper to your Director, and given the evidence reported, he asked you to give a presentation about the study findings during the weekly
seminar series. In your presentation, she has asked you to address the following questions (5a-d) based on the results of the published paper (Edited abstract is shown below):
A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management (Xavier Pi- Sunyer, M.D., Arne Astrup, M.D., D.M.Sc., Ken Fujioka et al. N Engl J Med 2015;373:11-22.
Background: Obesity is a chronic disease with serious health consequences, but weight loss is difficult to maintain through lifestyle intervention alone. Liraglutide, a glucagonlike peptide-1
analogue, has been shown to have potential benefit for weight management at a once-daily dose of 3.0 mg, injected subcutaneously.
Methods: We conducted a 56-week, double-blind trial involving 3731 patients who did not have type 2 diabetes and who had a body-mass index of at least 30 or a BMI of at least 27 if they had treated
or untreated dyslipidemia or hypertension. We randomly assigned patients in a 2:1 ratio to receive once- daily subcutaneous injections of liraglutide at a dose of 3.0 mg (2487 patients) or placebo
(1244 patients); both groups received counselling on lifestyle modification.
Results: At week 56, patients in the liraglutide group had lost a mean of 8.4±7.3 kg of body weight, and those in the placebo group had lost a mean of 2.8±6.5 kg (a difference of ?5.6 kg; 95%
confidence interval, ?6.0 to ?5.1; P<0.001). A total of 63.0% of the patients in the liraglutide group as compared with 37.0% in the placebo group lost at least 5% of their body weight (P<0.001).
Conclusion: In this study, 3.0 mg of liraglutide, as an adjunct to diet and exercise, was associated with reduced body weight and improved metabolic control.
Q5a. Construct a 2×2 table using figures shown in the abstract, and answer the following questions:
(i) What is the risk of losing at least 5% of body weight in all patients included in the study? [2 marks]
(ii) What is the risk of losing at least 5% of body weight in patients who were treated with liraglutide? [2 marks]
(iii) What is the risk of losing at least 5% of body weight in patients who were treated with placebo? [2 marks]
(iv) What is the relative risk of treatment with liraglutide versus placebo with regard to weight management? How would you interpret this relative risk estimate? [4 marks]
Q5b. If equal numbers of patients in the population were treated with liraglutide vs placebo treatment, what would be the expected population relative risk reduction (RRR) for liraglutide
treatment? How would you interpret this measure? [4 marks]
Q5c. How many patients need to be treated with liraglutide for one more patient to benefit compared with the placebo? What is this measure called? How would you interpret this measure [4 marks]
Q5d. How does the measure in question 5b differ from question 5c? [4 marks] 3
Imagine that you have read the full report of the original research study discussed in Question 5, now answer Questions 6 to 8:
Q6. What characteristics of the study would you consider in order to determine if its findings are valid? Include wider considerations of study quality/validity and give examples. (Q8 will address
relevance, and the next question will ask how to determine the importance of the findings…for this question, focus on the internal validity of the study) [16 marks]
Q7. What characteristics of the findings would you consider, in order, to determine if they are clinically meaningful and statistically significant? Include examples. (You’ve already addressed
validity…for this question, focus on how to determine the clinical significance and statistical significance of an effect reported in the study) [8 marks]
Q8. What characteristics of the study would you consider, in order, to determine if it is generalizable to your context? Explain your answers and provide examples. (Questions 6 and 7 have asked how
to determine if the study is valid, and how important the findings are….for this question, focus on how to determine if it is really relevant or generalizable to your practice.) [8 marks]