Observational Studies and Interventional Trials
There are two main types of research that people can take part in: observational studies and interventional trials
In observational studies, participants are not asked to do anything different or test out any treatments. They simply involve researchers measuring certain things in groups of people, usually to help understand more about possible ways of preventing an illness.
The kinds of things researchers would be interested in measuring would vary a lot from study to study but usually include several aspects of people’s general health and wellbeing as well as information on their daily activities such as diet and exercise.
The researches might just need to measure these once or they might follow people up over time to see how the things they are measuring change over time or differ between different groups of people (for example a group of older people versus younger people or a group of people with asthma versus a group without asthma).
There is usually more than one way to try to prevent or treat a particular illness but doctors may not know what the best way is. The way we find out is by asking people to take part in a clinical trial to compare the benefits and potential risks of each approach and see which way works best (this is called an Interventional Trial). An interventional trial could be in any of the following areas:
- Drug treatments
- Surgery – different surgical techniques or approaches
- Medical devices
- Nutrition, exercise or other lifestyle aspect
There are different kinds of interventional trial but very few involve people trying anything completely new.
Comparing current treatment approaches
Most trials simply compare two common approaches already being used to prevent or treat a specific medical condition to see which is more effective, safer or offers other advantages such as patient preference or being more cost effective, for example comparing
- two (or more) different drug treatments for reducing blood pressure
- whether different dietary approaches can improve symptoms of Irritable Bowel Syndrome
- keyhole surgery versus open surgery for removing an appendix
- whether surgery would be better than drug treatment in treating certain types of cancer
or a combination of treatments, such as
- whether drug treatment in addition to diet + exercise is beneficial for losing weight versus diet + exercise alone
Testing existing treatments in new diseases
For medical conditions where current treatments are not effective enough, doctors need to find alternatives. One approach is to test whether drug treatments which we know work well and are safe in other conditions could also be useful in this condition.
Testing new treatment approaches
In most disease areas, research is constantly underway to try to find better (either more effective or safer) treatments than the ones being used today. What exactly ‘more effective’ means depends on the disease area. For example for an antibiotic it could mean one that can kill bacteria which current antibiotics are resistant to. For pain relief medication, it could mean treatment which reduces pain faster or to a greater degree than another treatment.
Before a new treatment can be approved for use, the manufacturers need to demonstrate that it is equally or more effective and safe in patients compared to the current best available treatments. This requires a number of different stages– for more information see ‘Clinical Trial Phases’