HE201 Chapter Notes - Chapter 8: Case Series, Statistical Classification, Case Report
CHAPTER 8: CASE SERIES
8.1 Overview
• Case report: describes one patient
• Case series: describes a group of individuals with the same disease or who have
undergone the same procedure
o Can only be written and disseminated when a researcher has access to an
appropriate source of cases and when there is a compelling reason to write about
those cases
o This study approach can be useful for:
▪ Describing the characteristics of and similarities among a group of
individuals with the same signs and/or symptoms of a disease
▪ Identifying new syndromes and refining case definitions
▪ Clarifying typical disease progression
▪ Describing atypical presentations of a disease or unusual complications
from a treatment
▪ Developing hypotheses for future research
8.2 Case Definitions
• Researcher conducting case series must select one disease of interest, determine what
would be new and interesting about the study, and identify an appropriate and available
source of cases
• Case definition: spells out inclusion and exclusion criteria
• Participants may be selected from clinical locations
o ICD codes: diagnoses based on the international classification of diseases (AKA
international statistical classification of diseases and related health problems)
▪ ICD number can be part of case definition
▪ A code alone is rarely sufficient to cover all inclusion and exclusion criteria
• A more comprehensive case definition includes:
o A disease description
o Person
o Place
o Time
• Essential for any outbreak investigation, no matter which study approach is used to
investigate the epidemic
8.3 Special Considerations
• Might be constructed from primary data
o Interview about personal experiences
▪ Questionnaire
▪ Other qualitative techniques
• May be based solely on secondary data
o Study method most often used for case series
