General epidemiology/EBM Flashcards
Definitions, principles
Definition of Epidemiology
The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.
Origin of Epidemiology
John Snow - cholera outbreak in London. Maps used to isolate infected water source. Incorrect “miasma” theory, actually germs.
Ontology
Inquiry into how we define and experience reality.
Epistemology
Study of acquiring and processing new knowledge.
Methodology
Tools for organising and categorizing knowledge.
Independent Variable vs Exposure
Clinical research - variable which predicts/causes another (dependent) is the independent variable.
Epidemiology - same as above but dependent variable is called “outcome” and independent variable is called exposure instead. (*Take care with cause and epidemiological work)
Risk Factors
Exposures which alter the likelihood of the outcome of interest but have not been proved to be causal.
Descriptive vs Analytical Studies
Descriptive - asking who/what/where and when questions.
Example - a cross-sectional study establishing the prevalence of osteoarthritis in Manchester.
Analytical - asking why and how questions.
Example - a randomised controlled trial aiming to determine whether laparoscopic cholecystectomy or percutaneous biliary drainage is better for the management of acute calculous cholecystitis.
What is an experiment?
Where there is careful manipulation of one or more variables.
What was the first successful vaccination?
What is herd immunity?
Smallpox - Edward Jenner developed the vaccine in 1806. Last known case was in 1975.
Infection –> survivors develop immunity
Vaccination –> recipients develop immunity
If enough people within a population are immune, then an infectious agent will not have sufficient opportunities to encounter non-immune individuals and hence it will die out.
What is observational epidemiology?
Why is it important?
Looking for associations between two exposures and outcomes.
It allows us to anticipate complications/developments. E.g. Strep throat often followed by rheumatic fever.
Specifically, it is used to help us identify the morbidity and mortality associated with exposures, habits, lifestyle choices.
Four strands within epidemiology - give an example of each. 1 - Disease surveillance 2 - Diagnostic tests 3 - Trend analysis 4 - Experimental design
1 - detecting epidemics of infectious diseases, e.g. Influenza
2 - using population data to establish the sensitivity and specificity of new diagnostic tests
3 - changes to smoking related mortality across gender and ethnic groups
4 - prospective cohort study?
What is Evidence Based Medicine?
Integration of best research evidence with clinical expertise and patient values.
Knowledge of EBM principles will help you navigate the literature systematically, allowing you to make an informed clinical decision for your patients.
1 - What is best research evidence?
2 - What is clinical expertise?
3 - What are patient values?
1 - Clinically relevant basic sciences research or medical literature papers (there is a hierarchy of evidence).
2 - Using clinical skills and experience to identify each patient’s unique health state and diagnosis, plus accounting for risks and benefits for each potential intervention
3 - ideas, concerns and expectations…
Why is EBM important? (4 reasons)
Doctors need new information daily, there are too many new articles, textbooks are out of date and clinical knowledge declines (and gets outdated) with time.
