Case-Control Studies

OVERVIEW

  • a type of retrospective observational study
  • control patients are ‘matched’ using some criteria (age, gender), typically should have no history of the disease of interest and should be representative of the general population
  • begins with a definition of outcome or interest
  • aims to identify potential risk factors associated with outcomes
  • measures exposure to risk factors
  • outcome = in case and controls
  • odds ratio used to quantify risk, and can be adjusted for confounders (e.g. using logistic regression)

ADVANTAGES

  • quick, cheap and easy
  • cases and controls may be sampled from pre-existing databases
  • useful for identifying possible risk factors of a condition
  • useful for studying rare conditions and those with a long latency period following exposure to risk
  • not prone to loss to follow-up, unlike cohort studies
  • may be used as the initial study generating hypotheses to be studied further by larger, more expensive prospective studies

DISADVANTAGES

  • controls are often recruited by convenience sampling, and are thus not representative of the general population and prone to selection bias
  • subject to confounding (other risk factors may be present that were not measured)
  • not always possible in case-control studies to predict whether exposure to the risk factors preceded development of the disease or condition
  • relative risk can not be determined as the incidence or prevalence of the condition of interest cannot be estimated in the population
  • not suitable if exposure to the risk factors of interest is rare, as few of the cases and controls will have been exposed to them
  • cannot determine causation, only association

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.