Chapter 8

Question 1

A case series describes:

Answer 1

A group of patients who have the same disease condition or who have undergone the same procedure

Question 2

What is the difference between a case reports and a case series?

Answer 2

A case report describes one patient, whereas a case series describes a group of individuals.

Question 3

When can a case series be written?

Answer 3

1) When the researcher has access to an appropriate source of cases.
2) When there is a compelling reason to write about those cases.

Question 4

A case series study approach can be useful for:

Answer 4

1) describing the characteristics and similarities among a group of individuals with the same signs and/or symptoms of a disease.
2) Identifying new syndromes and refining case definitions.
3)  Clarifying typical disease progression.
4) Describing atypical presentation of a disease or unusual complications from a treatment.
5) Developing hypotheses for future research.

Question 5

How many participants do you need for case series studies?

Answer 5

A handful (rare conditions), a hundred, or a thousand.

Question 6

What are the beginning steps of a case series study?

Answer 6

1) Selecting one disease of interest
2)  Determining what will be new and interesting about the study
3) Identifying an appropriate and available source of cases

Question 7

What is the next step for case series studies?

Answer 7

Establishing a clear case definition that spells out inclusion and exclusion criteria.

Question 8

How can we select participants for a case series study?

Answer 8

From clinical locations that use ICD codes (International Classification of Diseases).

Question 9

What does the case definition include?

Answer 9

A disease description plus any relevant person, place, and time (PPT) characteristics. It may include the ICD number but a code alone is not sufficient.

Question 10

Case defintions are essential for any:

Answer 10

Outbreak investigation regardless of the study approach used to investigate the epidemic.

Question 11

When do we use the case series study approach?

Answer 11

When a source of cases is available, and no comparison group is required or available.

Question 12

What should you watch out for in case series studies?

Answer 12

A lack of generalizability

Question 13

What statistical measures are required for a case series study?

Answer 13

Only descriptive statistics are required

Question 14

When medical Records will be consulted as part of the data collection process, it is often helpful to create what?

Answer 14

A questionnaire that guides the extraction of information from these files.

Question 15

What is one of the limitations of relying on patient charts?

Answer 15

They usually contain only clinically relevant information.

Question 16

What might the absense of a specific note about a symptom or history mean?

Answer 16

That the exposure was present, but not recorded.

Question 17

What should a data extraction tool include?

Answer 17

A space to indicate the absence of a desired piece of information in the record.

Question 18

What should the researcher carefully consider during the analysis and interpretation stage of the research project?

Answer 18

The amount and type of missing information.

Question 19

What requirements protect patient privacy in case series studies?

Answer 19

1) Approval by a research ethics committee
2) Informed consent from participants and/or careful use of existing records
3) Removal of all potentially identifiable information prior to publication

Question 20

If pictures will be used, what must the researcher have?

Answer 20

Informed consent and documentation of consent even when there are no identifying marks.

Question 21

What kind of statistics do case series studies require?

Answer 21

1) Simple counts

2) Percentages
3) Morbidity
4) Mortality (Case fatality rate)

Question 22

What is the case fatality rate?

Answer 22

The proportion of people with a particular disease who die as a result of that condition

Question 23

What is the mortality rate?

Answer 23

The percentage of members of a population who die of any condition during a specified time period.

Question 24

What is the proportionate mortality rate?

Answer 24

The proportion of deceased members of a population whose death was attributable to a particular cause

Question 25

If a case series follows patients afterwards, what does this study become?

Answer 25

A cohort study in which all participants are defined by their disease status.