Types
One way of classifying clinical trials is by the way the researchers behave.
- In an observational study, the investigators observe the subjects and measure their outcomes. The researchers do not actively manage the study.
- In an interventional study, the investigators give the research subjects a particular medicine or other intervention. Usually, they compare the treated subjects to subjects who receive no treatment or standard treatment. Then the researchers measure how the subjects' health changes.
Another way of classifying trials is by their purpose. The U.S. National Institutes of Health (NIH) organizes trials into five different types:
- Prevention trials look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes.
- Screening trials test the best way to detect certain diseases or health conditions.
- Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition.
- Treatment trials test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
- Quality of life trials (supportive care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.
- Compassionate use trials or expanded access trials provide partially tested, unapproved therapeutics to a small number of patients who have no other realistic options. Usually, this involves a disease for which no effective therapy exists, or a patient who has already attempted and failed all other standard treatments and whose health is so poor, he does not qualify for participation in randomized clinical trials. Usually, case-by-case approval must be granted by both the FDA and the pharmaceutical company for such exceptions.
Read more about this topic: Clinical Trial
Famous quotes containing the word types:
“The bourgeoisie loves so-called “positive” types and novels with happy endings since they lull one into thinking that it is fine to simultaneously acquire capital and maintain one’s innocence, to be a beast and still be happy.”
—Anton Pavlovich Chekhov (1860–1904)
“He types his laboured column—weary drudge!
Senile fudge and solemn:
Spare, editor, to condemn
These dry leaves of his autumn.”
—Robertson Davies (b. 1913)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)