Observational and experimental studies

Question 1

In ___ studies, nature is allowed to take its course; no intervention.

Answer 1

observational

Question 2

In ___studies, there is an intervention and the results of the study assess the effects of the intervention

Answer 2

experimental

Question 3

Brief, objective report of a clinical characteristic or outcome from a single clinical subject or event, n = 1. What type of report?

Answer 3

Case report

For example, a 23-year-old man with treatment-resistant TB. No control group.

Question 4

Objective report of a clinical characteristic or outcome from a group of clinical subjects, n > 1…….. Is called?

Answer 4

cases in series

eg. patients at local hospital with treatment-resistant TB. No control group

Question 5

Identifies a group of people with the disease and compares them with a suitable comparison group without the disease……..what type of study?

Answer 5

case-control study

e.g., comparing cases of treatment-resistant TB with cases of nonresistant TB.

Question 6

Very useful for studying conditions with very low incidence or prevalence and it is almost always retrospective….. which study?

Answer 6

case-control study

Question 7

Population group is identified who has been exposed to risk factor is followed over time and compared with a group not exposed to the risk factor. Which study?

Answer 7

cohort study

• Outcome is disease incidence in each group
  eg. following a prison inmate population and marking the development of treatment-resistant TB.

Question 8

They are adequate to know the causes of an outcome.
To know the natural history of disease.
They are adequate when the exposure is rare.
They are useful when we study two or more outcome at the same time.

Which study?

Answer 8

Cohort study

Question 9

The presence or absence of disease and other variables are determined in each member of the study population or in a representative sample at a particular time. which study?

Answer 9

cross-sectional study

e.g., who in the community now has treatment-resistant TB.

Question 10

• The co-occurrence of a variable and the disease can be examined.
• Disease prevalence rather than incidence is recorded.
• The temporal sequence of cause and effect cannot usually be determined in a cross-sectional study

Which study?

Answer 10

cross-sectional study

Question 11

“ How much more likely ”
Incidence rate of exposed group DIVIDED by Incidence rate of unexposed group.
which risk?

Answer 11

Relative risk (for cohort study)

For Case-control study : use Odds Ratio
Odds ratio : AD/BC

Question 12

Incidence rate of exposed group MINUS Incidence rate of unexposed group

Answer 12

Attributable risk (for cohort study)

For Case-control study : use Odds Ratio
Odds ratio : AD/BC

Question 13

Research that involves the administration of a test regimen to evaluate its safety and efficacy.
which study?

Answer 13

experimental study

Question 14

describe the control grp. of experimental studies.

Answer 14

Subjects who do not receive the intervention under study; used as a source of comparison to be certain that the experiment group is being affected by the intervention and not by other factors.

In clinical trials, this is most often a placebo group. Note that control group subjects must be as similar as possible to intervention group subjects.

Question 15

3 phases of clinical trials for FDA

Answer 15

Phase One: Testing safety in healthy volunteers

Phase Two: Testing protocol and dose levels in small group of patient volunteers

Phase Three: Testing efficacy and occurrence of side effects in larger group of patient volunteers.
Phase Three is considered the definitive test.

Question 16

___ is a method used to prevent bias in research

Answer 16

Randomization

• Provides the best way to prove the effectiveness of a new agent or intervention

Question 17

The ___ group is made up of the people who get the most widely accepted treatment (standard treatment) for the disease

Answer 17

control

Question 18

The ___ group is made up of the people who get the new treatment being tested.

Answer 18

investigational

Question 19

______ means that neither subjects nor researchers who have contact with them know whether the subjects are in the treatment or comparison group.

Answer 19

Double-blind Randomized controlled clinical trial

• Double-blind RCT is the type of study least subject to bias, but also the most expensive to conduct.