MCQ Course in Pediatrics Al Yamamah Hospital June Dr M A Maleque Molla, FRCP, FRCPCH

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1 MCQ Course in Pediatrics Al Yamamah Hospital June Dr M A Maleque Molla, FRCP, FRCPCH Q1. Following statements are true in the steps of evidence based medicine except ; a) Convert the need for information into an answerable question. b) Track down the best evidence with which to answer that question. c) Critically appraise the evidence for its validity, impact, and applicability. d) Implement the result in clinical practice e) Integrate the evidence with our clinical expertise and our patient s characteristics and values. Answer: d. EVIDENCE BASED MEDICINE: Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values - Dave Sackett EBM approach requires three areas of knowledge when making clinical decisions: 1. Patient Values, -The concerns and expectations of the patient must be integrated into the clinical decisions 2. Clinical Expertise - the ability to use clinical skills 3. The Best Research Evidence valid and clinically relevant research mainly published as 5 Steps of EBM are; Defining Clinically Relevant Questions Searching for the Best Evidence Critical appraisal of evidence for validity, clinical relevance, and applicability Applying the Evidence Evaluating the Performance of EBM 5 steps as the five A s: 1. Ask a question 2. Access the information 3. Appraise the articles found 4. Apply the information 5. Audit

2 Q2. Which statement is true for PICO in Evidence base medicine a) Method of obtaining evidence of treatment effectiveness b) Used to help to formulate question from clinical scenario c) A unit of measurement d) Method of patient management e) A method of collecting evidence from the source Answer: b. Q 3. In evidence base medicine PICO stands for a) Product(Medicine), Intervention, compare outcome b) Patient, Intervention, comparison, Outcome. c) Patient, Investigation, comparison of medication, Outcome d) People, intervention, Comparison, Outcome. Answer: b. PICO: To formulate a good question, practitioners apply the acronym P-I-C-O as a framework to outline the clinical question: P -Patient, Population, or Problem (or Disease or Condition) I -Intervention, Exposure, Maneuver C -Comparison or Control O Outcome Q 4. When planning a research study, all the following steps are included except: a) Identifying a researchable problem b) A review of current research c) Statement of the research question d) Conducting a meta-analysis of the research e) Developing a research plan Answer Q. 4: d. Q 5. Select all of the statements which are true regarding clinical study; a) In a cluster randomized trial each individual in a cluster is randomized to a different treatment. b) A multicenter study may be experimental or observational. c) Different study protocols are used in two or more of the centers in a multicenter study. d) The unit of observation in a medical study is always the individual person Answer Q. 5: b. The clusters are randomized to the different treatments in a cluster randomized trial; thus all individuals in a cluster receive the same treatment True statement The same study protocol is used in all the centres in a multicentre study. The unit of observation in a medical study may be the individual but it also may be the smallest group of individuals

3 Q. 6 What correct order of evidence from lowest to highest according to evidence of hierarchy; a) Meta analysis, Cohort study, Case Control study, Systemic review, RCT b) Meta analysis, Systemic review, RCT Cohort study, Case Control study. c) Case Control study, Cohort study, RCT, Systemic review, Meta analysis. d) RCT, Systemic review, Meta analysis, Cohort study, Case Control study. Answer: c. Fig. Evidence of hierarchy Pyramid Q. 7. In a randomized controlled trial, the following type of bias is reduced by randomization: a) Ascertainment bias b) Recall bias c) Selection bias d) Publication bias Answer Q 7.: c.

4 Advantages of RCT: Allows rigorous evaluation of a single variable in a precisely defined patient group e.g. effect of drug treatment versus placebo Prospective design i.e. data are collected on events that happen after you decide to do the study Uses hypotheticodeductive reasoning; i.e. seeks to falsify, rather than confirm, its own hypothesis Potentially eradicates bias by comparing two otherwise identical groups Allows for meta-analysis; i.e. combining the numerical results of several similar trials at a later date Q. 8. Select all of the following statements which are true regarding clinical trials; a) A double-blind trial always involves a placebo treatment. b) A positive control treatment is a one which really works. c) A control treatment must involve the use of a placebo d) All ideal clinical trials are randomized and controlled Answer Q. 8: d. a). A double-blind trial always involves a placebo treatment. The patient could be receiving a standard treatment which is used as a basis for comparison of the novel treatment under investigation, in which case a placebo would not be used. b). A positive control treatment is a one which really works. A positive control treatment is one which contains an active ingredient as opposed to a negative control which is either the absence of treatment or a placebo. c). A control treatment must involve the use of a placebo If the control treatment is a standard treatment which is compared to a novel treatment, and both appear identical, a placebo is not required d). All clinical trials are randomized and controlled The ideal clinical trial should include the features of control and randomization, but not all clinical trials are ideal Q. 9. Select all of the following statements which you believe to be true in systematic review: a) Is an integral part of evidence based medicine b) Is a particular form of meta-analysis. c) Is a formalized and stringent process of refereeing papers for submission to scientific journals. d) May suffer from the disadvantage of publication bias Answer Q 9: a, d Systematic Review: Def: A document written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question.

5 The systematic review is created after reviewing and combining all the information from both published and unpublished studies (focusing on clinical trials of similar treatments) and then summarizing the findings Advantages Exhaustive review of the current literature and other sources (unpublished studies, ongoing research) Less costly to review prior studies than to create a new study Less time required than conducting a new study Results can be generalized and extrapolated into the general population more broadly than individual studies More reliable and accurate than individual studies Considered an evidence-based resource Disadvantages Very time-consuming May not be easy to combine studies May suffer from publication bias Q. 10. Selecting the appropriate types of research following are true except; a) Testing the efficacy of a drug treatment, preferred study is RCT. b) For the validity & reliability of a new diagnostic test, cross sectional survey is preferred. c) For screening test to pick up a pre symptomatic disease, preferred test is case control study. d) To determine the prognosis of a disease, prospective cohort study is preferred. Answer Q. 10: c. Is the design for the research is appropriate? This question is best addressed by considering what broad field of research is covered by the study. Therapy: Testing the efficacy of drug treatments, surgical procedures, or other interventions: Preferred study design is randomised controlled trial Diagnosis: Testing whether a new diagnostic test is valid and reliable: Preferred study design is cross sectional survey Screening: Demonstrating the value of tests which can be applied to large populations and which pick up disease at a pre-symptomatic stage. Preferred study design is cross sectional survey Prognosis: Determining what is likely to happen to someone whose disease is picked up at an early stage: Preferred study design is longitudinal cohort study Causation: Determining whether a putative harmful agent is related to the development of illness e.g. environmental pollution: Preferred study design is cohort or case-control study, depending on how rare the disease is, Case reports may also provide crucial information

6 Q. 11. For a meta-analysis following statements are true except: a) Concerns the statistical analysis of a very large data set from a clinical trial or observational study. b) Is a particular type of systematic review. c) Can use a forest plot to determine whether the results from the separate studies are compatible and assess the significance of the individual and overall effects. d) Has results which are statistically heterogeneous if there is considerable variation between the estimates of the effects of interest from the various studies. Answer Q. 11: a Meta-Analysis: Def: A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power Advantages Greater statistical power Confirmatory data analysis Greater ability to extrapolate to general population affected Considered an evidence-based resource Disadvantages Difficult and time consuming to identify appropriate studies Not all studies provide adequate data for inclusion and analysis Requires advanced statistical techniques Heterogeneity of study populations Q.!2. Select all of the following statements which are true for the statement 95% confidence interval for a proportion : a) Cannot be calculated if the sample size is small. b) Is the interval within which 95% of sample proportions would lie if we were to take repeated samples of a given size from the population. c) Is the interval within which we expect the population proportion to lie with 95% certainty. d) Is wider than the 99% confidence interval for the proportion Answer: b, c. Confidence interval: Def: a range of values for a variable of interest constructed so that this range has a specified probability of including the true value of the variable. The specified probability is called the confidence level, and the end points of the confidence interval are called the confidence limits It is conventional to create confidence intervals at the 95% level so this means that 95% of the time properly constructed confidence intervals should contain the true value of the variable of interest

7 Q. 13. Which of the following statements are true regarding P-value : a) The probability that the null hypothesis is true. b) The probability that the alternative hypothesis is true. c) The probability of obtaining the observed or more extreme results if the alternative hypothesis is true. d) The probability of obtaining the observed results or results which are more extreme if the null hypothesis is true. e) Always less than Answer: d Q. 14. Following statements are true regarding p value in research except; a) Prefers to the probability that any particular outcome would have arisen by chance. b) The smaller the P value the less likely the data was by chance and more likely due to the intervention. c) Finding P=0.1 means it the difference in finding is significant. d) A P value of less than 1 in 20 considered as "statistically significant. Answer Q. 14.: c. P value: Probability describes the likelihood of an event occurring It is usually measured on a scale of 0 to 1 where an impossible event is given a value of 0 and an event that is certain to occur is given a value of 1 What dose p value mean? The P value is the probability of observing the results of a trial when the null hypothesis is true. The probability that any particular outcome would have arisen by chance and not a true difference Smaller the p value greater the likelihood that the difference observed is a true difference p<0.05= One possibility in 20 that the difference is due to chance and 19 out of 20 possibility that it is a real difference= Significant difference P<0.01= one in 100 possibility due to chance & 99 out of 100 possibility it is real difference = Highly significant P<0.001= very highly significant Q. 15. Select all of the following statements which are true regarding odds ratio: a) Is an estimate of the relative risk when the incidence of the disease is rare. b) Is calculated in a case-control study because the relative risk cannot be estimated directly. c) Is equal to zero when the odds of being a case in the exposed and unexposed groups are equal.

8 d) Is the ratio of the probability of being a case in the exposed group to the probability of not being a case in exposed group. e) Cannot be negative. Answer Q. 15: a, b,e a) OR is an estimate of the relative risk when the incidence of the disease is rare because prevalence is unknown b) Odd Is calculated in a case-control study because the relative risk cannot be estimated directly. It is not possible to estimate the risk of disease (and therefore the relative risk) in a case-control study as the number of subjects with and without the disease of interest is selected (often in equal numbers) as part of the design of the study. c) The odds ratio is equal to one (unity) when the odds of being a case in the exposed and unexposed groups are equal. d) The odds ratio is the odds of being diseased in the group exposed to the factor divided by the odds of being diseased in those unexposed to the factor e) The odds ratio is always greater than zero although it can be less than one Odds & Odds ratio: Odds = Probablity that something will or will not happen. Odds refers to the ratio of the number of people having the good event to the number not having the good event The odds ratio is the ratio of the odds with experimental treatment and that of control Example: Treatment Ibuprofen 400 mg Total number of patients treated No Achieve 50% pain relief Placebo No Not achieve 50% pain relief Table1. Trial of ibuprofen in acute pain Odds refers to the ratio of the number of people having the good event to the number not having the good event: so odds in the experimental event = 22/18 = 1.2. Placebo group odds are 7/33=0.21 The odds ratio is the ratio of the odds with experimental treatment and that of control, Odds ratio =1.2/0.21 = 5.7 Values greater than 1 show that experimental is better than control, and if a 95% confidence interval is calculated Q. 16. Which statement is true regarding the standard deviation?; a) Standard deviation is the square root of the variance b) It is a measure of variability c) It is an approximate indicator of how numbers vary from the mean d) All of the above e) None of the above Answer Q. 16: d.

9 Q. 17. Approximately what percentage of scores fall within one standard deviation of the mean in a normal distribution? a) 34% b) 68% c) 95% d) 99.7% Answer Q.17: b Fig. Normal distribution curve and calculation of 1 sd, 2 sd, 3 sd Q. 18. Four children have an IQ test. Their scores are 96, 100, 106, 114. Which of the following statements is true? a) The mean is 103. b) The mean is 104. c) The median is 100. d) The median is 106. Answer Q. 18: b Mean, Median & Mode Mean of a sample or a population is computed by adding all of the observations and dividing by the number of observations; Population mean = μ = ΣX / N or Sample mean = x = Σx / n ΣX = sum of all the population observations, N = number of population Mean = Σx / n = ( ) / 4 = 104 Median is the middle value of an observation. If there is an odd number of observations, the median is the middle value. If there is an even number of observations, the median is the average of the two middle values. So median is the average of the two middle scores. Thus, the median is ( ) / 2 = 103.

10 Mode is mode observed value e.g. Samples of IQ tests: 96, 100, 100, 106, 104; Mean =101, Median= 100, Mode is 100. Q. 19. A screening test was devised for depression and blind comparison was made with a gold standard for diagnosis of depression among 200 psychiatric outpatients. Among the 50 outpatients found to be depressed according to the gold standard, 35 patients were +ve for the test. Other 150 patients found not to be depressed according to the gold standard, 30 patients were found to be positive for the test. Following parameters which one is true(corrected to the nearest decimal place): a) The sensitivity was 80% b) The specificity was 80% c) The positive predictive value was 70% d) The negative predictive value was 88.9% e) The prevalence of depression was 25% Answer Q. 19: b Definitions: Depression Present Absent Test Fig. 2x2 Table

11 Sensitivity = The proportion of subjects with the disease correctly diagnosed by the test = 35/50 = 0.7x100 = 70%. Specificity = The proportion of subjects without the disease correctly excluded by the test = 120/150 = 0.8x100 = 80%. Positive predictive value = The proportion of subjects with a positive test who have the disease = 35/65 = 0.538x100 = 53.8%. Negative predictive value = the proportion of subjects with a negative test who do not have the disease = 120/135 = 0.889x100= 88.9%. Negative predictive value = the proportion of subjects with a negative test who do not have the disease = 120/135 = 0.889x100= 88.9%. Q. 20. Abstract: High flow therapy versus hypertonic saline in bronchiolitis: randomised controlled trial; Mercedes Bueno Campaña1 et all; Arch Dis Child2014 It was a Randomised Clinical Trial from 1 October 2010 to 31 December 2012 In two urban secondary (no PICU available) paediatric hospitalisation units. Hospitalised children aged up to 6 months with moderate acute bronchiolitis (Respiratory Distress Assessment Instrument, RDAI 4), were randomised to HHHFNC or HSS. All of them received epinephrine as bronchodilator. Primary outcome was difference in mean Respiratory Assessment Change Score (RACS) between both groups measured in six previously defined consecutive moments. Secondary outcomes were difference in mean comfort scores in this period, LOS and rate of PICU admission. Q. Applying PICO in this research, all are true except; a) P= patients hospitalised in Pediatric unit b) I= High flow oxygen via nasal canula or Hypertonic saline c) C= between High flow oxygen verses Hypertonic saline d) O= difference in respiratory mean RACS,difference in comfort score length of hospital stay & PICU admission Answer: a; P= Children aged up to 6 months with moderate acute bronchiolitis *HHHFNC =heated humidified high-flow nasal cannula oxygen therapy