EBM I - Study Design

Question 1

group of patients recieving new drug and control group receiving placebo or gold standard

Answer 1

controlled/comparative clinical trial

Question 2

group of patients who receive new drug and a control group who receives placebo or gold standard treatment, are then randomized to different trial groups

Answer 2

randomized control trial

Question 3

researchers and those involved in this study do not tell participants if they are being given a test treatment or control treatment

Answer 3

single blind randomized control trial

Question 4

neither patients nor researchers in this study are aware of who is receiving placebo and who receives treatment, useful for preventing bias due to demand characteristics or placebo effect

Answer 4

double blind randomized control trial

Question 5

patient’s guessing their assignment - treatment or placebo - introducing bias into a study

Answer 5

demand characteristics

Question 6

both researchers and participants know which treatment is being administered, can still be randomized, may also be uncontrolled with all patients receiving the same treatment

Answer 6

open-label clinical trial

Question 7

study where half of the patients receive active treatment for a period of time, followed by placebo, other half receives placebo first followed by experimental treatment, danger of carryover effect where a drug may continue to have an effect even after it is withdrawn which is resolved with “washout” period, each person is his or own control

Answer 7

cross-over study

Question 8

detailed presentation of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient, may contain demographic profiles but usually described unusual or novel occurences

Answer 8

case report

Question 9

describes the presentation of a disease in a number of patients with no control or comparison group

Answer 9

case series

Question 10

looks back to the past for exposures/non-exposures to a possible risk factor, and examines whether the risk factor was present more frequently in cases than in controls, to solve, start by splitting people into two groups based on disease outcome, yes/no box

Answer 10

case-control

Question 11

a group of people are split into two groups based on exposure to a risk factor, then followed over time to determine which will develop outcome/disease, yes/no box

Answer 11

cohort study

Question 12

starts with a group of people who have recently been diagnosed with a disease, and are followed overtime to determine prognosis after introduction of a risk factor

Answer 12

inception cohort

Question 13

are typically prospective studies since they are looking forward from a specific point in time

Answer 13

cohort studies

Question 14

study where a researcher has access to information about the prior exposures of a particular group of people, splits the group into two based on the exposure to a risk factor, and sees whether the risk factor exposure is related to the disease or outcome of interest at a later time

Answer 14

historical/retrospective cohort study

Question 15

observational study analyzing data collected from a population at a specific point in time, examining exposure and outcome at the same time

Answer 15

cross-sectional study

Question 16

repeated observations of the same subjects over a period of time

Answer 16

longitudinal study

Question 17

Risk t and Risk c

Answer 17

risk of death in treatment and control groups

Question 18

baseline risk

Answer 18

Risk c

Question 19

Risk c - Risk t, difference in absolute risk -probability of events- between control and treatment groups, percentage

Answer 19

ARR

Question 20

1/ARR, number of patients who would need to be treated to prevent and adverse event, directly summarizes the effort needed to gain potential clinical benefit

Answer 20

number needed to treat, NNT

Question 21

Risk t / Risk c, relative probability of the event in the treatment or exposure group compared to the standard of care/control group, null value = 1, <1.0 decreased risk

Answer 21

relative risk, RR

Question 22

ARR/Risk c

Answer 22

relative risk reduction