drug lit

• used to gain and understand of disease prevalence and treatment effectiveness
• NOT efficacy!!!!
• real world studies 
• more representative of populations 
• allow inclusions that are usually excluded 
• short time frame 

effectiveness: does the drug work and do what it is supposed to in the real world (look at compliance, side effects, cost, dosing schedule)

efficacy: does the drug mechanism work in an ideal population 

• case report
• case series
• case- control
• cross sectional
• cohort 

• describes some newsworthy clinical occurrence 
• can alert others to look out for the same occurrence
• hypothesis generating 
• clinical narrative

not primary literature 

• certain characteristics of a group of pt are described and published 
• short period of time
• no controls
• hypothesis generating 

easy to write and the observations may be useful to investigators designing a study to evaluate causes or explinations

good after a  product launch

very bias= not conclusive 

studies that are undertaken to test 1 or more specific hypothesis about an exposure and disease risk

exposure------outcome

asks what happened- retrospective

bengin with absence or presence of an outcome and look back in time to see possible risk factors

select case based off disease

select controls based off no disease

select cases and controls from same population

good for hypothesis generating and testing!

matching is often used to associate controles with cases on age and gender 

dont want to make wrong associations or conclusions 

good for rare diseases or events, examing conditions that develop over a long period of time and for primary hypothesis

quick and least evepsive for preliminary data

depend completely on high quality existing records

require compromises between what rresearch wantes to study

selection of control group hard

largest number biases 

• asks whats happening (a survey)
• not based on a period of time, one point in time analysis
• exposure and outcome are taken at the same point in time
• can address questions that come about from case series 

quick and cheap

good for determining the status quo of a disease or condition or diagnostic procedures

only a snapshot in time- could be misleading information 

• asks what will happen= prospective
• group of people who have something in common and who reain part of a group over an extended period of time

• select by some defining characteristics that is thought to be a precursor 
• examine what happens to the disease over time 

2 groups of people (1 has exposure and other does not have exposure)

investigator follows each group to measure disease incidence 

cohort study where information is collected in the past and kept in records

aka retrospective cohort study

design of choice for studying the cause of a condition, course of the disease or the risk factors

cause cannot be proven because only observatins and no intervention

many years needed- can loose patients