Review Question - QID 210429

This study is collecting information/epidemiological factors and then following the patients forward for certain outcomes making it a prospective cohort study.

Observational studies (of which cohort studies are a subtype) can be either prospective or retrospective. Cohort studies compare a group with a given risk factor to a group without the risk factor to see if there is an increased likelihood of developing the disease. An example of a cohort study is whether patients who drink alcohol are more likely to get cirrhosis. The computed result of a cohort study is a relative risk value. A prospective cohort first starts with the exposure and then follows patients forward to look for the outcome later in time. A retrospective cohort study first looks at risk factors and then checks to see if the outcome of interest had occurred.

Incorrect Answers:
Answer 1: Cross-sectional study assesses disease status and exposure/risk factors at the same point in time. It may show prevalence but not incidence.

Answers 2 & 4: A case-control study compares the odds of being exposed between patients with disease and patients without the disease. It compares cases (with the disease) and controls (without the disease). A prospective study would follow patients forwards whereas a retrospective study would look back at certain outcomes then assess for certain exposures.

Answer 5: Retrospective cohort study first groups patients by risk factors and then subsequently looks at their outcomes. Because this study is going forward, it is not retrospective despite the fact that the outcomes have already occurred (in contrast to a prospective cohort study where the individuals are followed forward).

Bullet Summary:
A prospective cohort study compares a group with a risk factor to a group without a risk factor and follows patients forward in time to assess for the outcome of interest.