Important of evidence in medicine Flashcards
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
Disease prevalence
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
Temporal relationship
What is the best way of addressing bias?
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
Considering potential bias in your study
What is the role of evidence based practice in clinical medicine?
Clinical findings- how to properly gather + interpret findings from history and physical examination
Aetiology- identifying causes of disease
Clinical manifestations of disease- knowing how often and when disease causes clinical manifestations
Differential diagnosis
Diagnostic tests
- how to select and interpret diagnostic tests, to confirm or exclude a diagnosis
Prognosis
-how to estimate a patient’s likely clinical course over time and anticipate likely complications
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.
List and the hierarchy of evidence in study design
Systematic review and meta-analyses, RCT, cohort studies, case-control studies, ecological studies, descriptive/ cross-sectional studies, case report/ series
Describe advantages systematic review and meta analyses
Way of getting round problems of expense and needing large sample size in RCTs, can use smaller studies and pool results
Describe an RCT
Gold standard for clinical trials + surgical interventions, they are expensive and need large sample size to demonstrate an effect. The people participating in the trial are randomly allocated to either the group receiving the treatment under investigation or to a group receiving standard treatment (or placebo treatment) as the control. Randomization minimises selection bias and the different comparison groups
Describe cohort studies
You have a group of people before they develop condition then look at exposures and risk factors. They are followed over time to see who gets disease of interest. Better for common conditions and less prone to bias
Describe case-control studies
Two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Useful for rare conditions.
Describe ecological studies
Type of descriptive study which uses correlations between different populations using different exposures. EG Alcohol consumption by country per capita vs liver cirrhosis rate
Describe descriptive/ cross-sectional studies
Based on routinely collected data, difficult to show a causal relationship. A cross-sectional study is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time
Descriptive case report
Description of single/ series of cases. This is NOT evidence used to support practice but can be useful in picking out new syndromes or conditions
Why does EBM matter to clinicians?
patient care, patient safety, medical knowledge, professionalism, revalidation
How are epidemiological skills applied to clinical decision making
Much of what underpin clinical medicine is epidemiological evidence (the study of the distribution of health-related states/events and the determinants of health-related states in specified populations, and the application of this study to control health problems- to promote, protect and restore health)
Why were studies suggesting MMR caused autism flawed?
They didn’t explain 3 factors- bias, chance and confounding factors
