3 Why evidence-based medicine? Flashcards
Q: Which of the following is NOT important to consider when assessing whether a relationship is causal? o Experimental evidence o Consistency o Plausibility o Disease Prevalence o Specificity
A: Disease Prevalence
Q: Which criteria is essential for a casual pathway between an exposure and an outcome? o Consistency with other investigations o Temporal relationship o Experimental evidence o A strong association o Plausibility
A: Temporal relationship
Q: Bias leads to an incorrect estimate of an association. The best way of addressing bias is;
o Through statistical analysis e.g. regression
o By increasing the power of the study
o Considering potential bias in your study
o Through Standardisation
o By repeating the study
A: Considering potential bias in your study
Q: Which is the most important when deciding whether to prescribe homeopathic Medicine?
o Some of your patients report improvements following Homeopathy
o Remedies retain small amounts of the original active substance
o A systematic review
o The ability of water to retain a memory of substances
o The NHS already spends £4 million a year on homeopathic treatment
A: A systematic review
Q: Where did the concept of evidence based medicine emerge from? suggesting that? It is?
A: the literature on ‘critical appraisal’ suggesting that clinicians should use critically appraised information in clinical practice for optimal care of their patients
Methods to critically appraise clinical information and classify it according to the strength of evidence
Q: What are the roles of evidence based practice in clinical medicine? (8)
A: ACCDDTPP
Clinical findings – how to properly gather and interpret findings from the history and physical examination
Aetiology – how to identify causes for disease (including its iatrogenic forms)
Clinical manifestations of disease – knowing how often and when a disease causes its clinical manifestations
Differential diagnosis – when considering the possible causes of a patient’s clinical problem, how to select those that are likely, serious and responsive to treatment
Diagnostic tests – how to select and interpret diagnostic tests, to confirm or exclude a diagnosis, based on considering their precision, accuracy, acceptability, expense, safety, etc
Prognosis – how to estimate a patient’s likely clinical course over time and anticipate likely complications of the disorder
Therapy – how to select treatments to offer a patient that do more good than harm and that are worth the efforts and costs of using them
Prevention – how to reduce the chance of disease by identifying and modifying risk factors and how to diagnose disease early by screening
Q: What are the criticisms of evidence based medicine?
A: It is impossible for any clinician to have the time to critically appraise even one article per week let alone the number that would need to be appraised to answer questions (estimated at 3.5 per clinical session) arising in a busy practice
Governments healthcare commissioners and providers have used the jargon of EBM to justify decisions, directives, or incentives that are seen by clinicians as inappropriate
Q: Why does evidence based medicine matter to clinicians? (7)
A: BETTER SERVICE FOR PATIENTS (most important reason)
Patient Care and Safety
Medical Knowledge- Part of professional practice.
Revalidation. Constantly have to demonstrate you are up to date and applying evidence in practice through revalidation (every 5 years for consultants).
Professionalism
Practice-Based Learning and Improvement
Interpersonal and Communication skills
Q: What is the relationship between evidence based medicine and clinical decision making?
A: Evidence based medicine does NOT replace clinical decision making but is only a tool
Q: What is the hierarchy of studies? (7)
A: Systematic reviews and meta-analyses
Randomised controlled trials
Cohort studies
Case-control studies
Ecological studies
Descriptive/cross-sectional studies
Case report/series
Q: Systematic reviews and meta-analyses. Way of getting round? Conducted?
A: – A way of getting around the problems of expense and needing a large sample size for Randomised Controlled Trials.
– Can use a series of smaller studies in systematic review to select trials based on quality and then do an analysis. Results of studies pooled to essentially give you results for a larger study.
Q: Describe randomised controlled trials. When may they need to be large? Price? How are they conducted? Negatives?
A: – Selection for people you want to experiment on.
– GOLD STANDARD for clinical trials and surgical interventions.
– HOWEVER with some treatment effect might be weak so trials may need to be very large to demonstrate an effect.
– Expensive
Comparison against Placebos (controls)
People are allocated at random to receive one of several clinical trials
Negatives:
o Inappropriate controls
o Missing trials (if you hide the effects of certain trials to make results bias)
Q: Cohort studies. Involves? Looks at? Conduction? Bias?
A: – Involves use of a group of people before they develop a condition. Then look at exposures and risk factors.
– They are then followed up over time to see which succumb to disease of interest. Better for common conditions.
– Less prone to bias.
Q: Case control studies. What are they? What are they more useful than? in what situation?
A: – Cases of people with condition compared with people without the condition(controls).
– More useful for rare conditions than Cohort studies.
Q: Ecological studies. What type of study? Uses? Example?
A: – Type of descriptive study.
– Uses correlations between different populations, using different exposures.
– E.g. Alcohol consumption by country per capita vs liver cirrhosis rates.
