Epidermiology Flashcards
A True positive B False positive
C False negative DTrue negative
A and B = Positive
C and D = Negative
A and D = True
B and C = False
Ok sooo to fill in the truth table and a short cut to remember some formula
Positive people are at the top
Negative people at the bottom
True is the first and last
Sensitive people get cut down (top to bottom) with the left hand (a and c)
Specific people raise their right index finger to be specific (bottom to top on right hand side b and d)
Retro Cohort vs Case control vs Cross sectional Study
In Retrospective Cohort Study, you begin by travelling back in time, you take two groups (Exposed and Non-exposed), you return to the present day and assess the same recruits for the outcome (Disease or No disease);
U looked in patient notes and look for Exposure (The study topic ) then follow them Whether they develop or have relation with the Outcome (The Disease or many diseases )
U dont know the patient and you dont know whether the patient have developed the disease or not
In Case-Control Study, you recruit your participants from the present day in two groups (Disease and No Disease), you then travel back in time and assess them for (exposure or non-exposure to) risk factor;
U know the patient with the Disease (Outcome )
U take careful History for the associated Risk exposure (Exposure ) (Can be many exposure and risk factors )
Explore many exposures before the outcome of the disease
Problem - take a medical history - recall bias - to reduce use hospital notes
In Cross-sectional Study, you make all observations in real-time- Exposure/Non-exposure and Outcome/No outcome.
Useful for looking relationship between multiple disease and multiple exposure
Eg . Obesity and No obesity with High cholesterol and Low cholesterol
And you compare the Exposure Prevalence of High cholesterol in Obese / High cholesterol in NON obese
a/a+c divided by b/b+d
You will get a ratio if you Divide them (the ratio is the times eg . 23 times high risk for Obese person to have or develop hypercholesterolemia )
called the Outcome Prevalence
