What are case-control studies?

Case-control studies are observational studies (which do not perform intervention) in which the outcome is used to assess exposure.

In what kind of situation could we use the case-control study?

Case-control studies evaluate odds measures.

We can use it to evaluate rare or infrequent diseases or when the clinical condition to be investigated takes a long time to develop.

For example, we would like to know if fiber consumption decreases the chances of developing colorectal cancer.

We selected cases of patients with colorectal cancer and compared them with controls without colorectal cancer. We applied a questionnaire to detail fiber consumption throughout the life of these patients.

What is the advantage of carrying out a case-control study?

These studies are inexpensive and much simpler to carry out since a long follow-up period is not necessary.

What are the disadvantages of case-control studies?

Since we depend on the patients' reports of their previous conditions and exposures (in the previous example, we need the patient to remember the details of his diet throughout his life), the case-control study is subject to recall bias.

An important detail is that in case-control studies, we should use risk measures, and we should prefer the odds measures of association.

Thus, in this study design, the clinical question CANNOT be: does fiber consumption decrease the RISK of developing colorectal cancer?

Doubts between risk and odds? See in LINK

This text was written by:

Francisco Tustumi,

FMUSP Digestive System Surgeon

Follow ABCD journal on social media!

INSTAGRAM: https://www.instagram.com/revistaabcd/

TWITTER: https://twitter.com/revista_abcd

FACEBOOK: https://www.facebook.com/Revista-ABCD-109005301640367

LINKEDIN: https://www.linkedin.com/company/revista-abcd