Prospective clinical trial meaning

Correctly identifying whether a study is considered by NIH to be a clinical trial is crucial to how you will: Select the right NIH funding opportunity announcement for your research study Write the research strategy and human subjects sections of your grant application and contract proposal Comply with appropriate policies and regulations, including registration and reporting in ClinicalTrials.

NIH Definition of a Clinical Trial A research study in which one or more human subjects are prospectively assigned prospectively assigned The term "prospectively assigned" refers to a pre-defined process e. Use the following four questions to determine the difference between a clinical study and a clinical trial: Does the study involve human participants?

Are the participants prospectively assigned to an intervention? Is the study designed to evaluate the effect of the intervention on the participants? Is the effect being evaluated a health-related biomedical or behavioral outcome? Note that if the answers to the 4 questions are yes, your study meets the NIH definition of a clinical trial, even if… You are studying healthy participants Your study does not have a comparison group e.

Resources to Clarify the Definition Case Studies These simplified case studies illustrate the differences between clinical trials and clinical studies.

Decision Tree Print this decision tree for an easy reference for the four questions that identify a clinical trial.

This page last updated on August 8, Case-Control studies are usually but not exclusively retrospective, the opposite is true for cohort studies. The following notes relate case-control to cohort studies:.

Cohort studies are usually but not exclusively prospective, the opposite is true for case-control studies. The following notes relate cohort to case-control studies:. Download a free trial here.

Prospective vs. Retrospective Studies Prospective A prospective study watches for outcomes, such as the development of a disease, during the study period and relates this to other factors such as suspected risk or protection factor s.

Retrospective A retrospective study looks backwards and examines exposures to suspected risk or protection factors in relation to an outcome that is established at the start of the study. In essence, the investigators are jumping back in time to identify the study cohort at a point in time before the outcome of interest death occurred. They can classify them as "exposed" or "unexposed" based on their employment records, and they can use a number of sources to determine subsequent outcome status, such as death e.

Key Concept: The distinguishing feature of a retrospective cohort study is that the investigators conceive the study and begin identifying and enrolling subjects after outcomes have already occurred. Retrospective cohort studies like the one described above are very efficient for studying rare or unusual exposures, but there are many potential problems here.

Sometimes exposure status is not clear when it is necessary to go back in time and use whatever data is available, especially because the data being used was not designed to answer a health question. Even if it was clear who was exposed to tire manufacturing chemicals based on employee records, it would also be important to take into account or adjust for other differences that could have influenced mortality, i.

If smokers were older than non-smokers, then the unequal age distribution would exaggerate the strength of association between smoking and lung cancer.

For example, it might be important to know whether the subjects smoked, or drank, or what kind of diet they ate. However, it is unlikely that a retrospective cohort study would have accurate information on these many other risk factors.

The video below provides a brief explanation of the distinction between retrospective and prospective cohort studies. Intervention studies clinical trials are experimental research studies that compare the effectiveness of medical treatments, management strategies, prevention strategies, and other medical or public health interventions. Their design is very similar to that of a prospective cohort study. However, in cohort studies exposure status is determined by genetics, self-selection, or life circumstances, and the investigators just observe differences in outcome between those who have a given exposure and those who do not.

In clinical trials exposure status the treatment type is assigned by the investigators. Ideally, assignment of subjects to one of the comparison groups should be done randomly in order to produce equal distributions of potentially confounding factors. Sometimes a group receiving a new treatment is compared to an untreated group, or a group receiving a placebo or a sham treatment.

Sometimes, a new treatment is compared to an untreated group or to a group receiving an established treatment.