25 November 2017
CLINICAL RESEACH IN CARDIOLOGY
Over time, the art of medicine joined science.
In the past, several medical discoveries have been made as the result of errors or purely by chance (example: discovery of penicillin). Nowadays, the vast majority of medical discoveries are the result of rigorous research methods (discovery of insulin).
There are many legends about substances with medicinal effects. Are they true?
Myth or reality, an example!
Let’s take an example. You are told that eating a dry pea per day reduces cholesterol…
Myth or reality?
This is how clinical research intervenes. A question needs an answer: a dry pea per day lowers cholesterol levels, and with research, we get the answer to our question.
To check this assumption, we compare two groups of similar people with various basic characteristics (age, gender, etc). The first group takes a dry pea per day for a determined period of time and the second group (the control group) takes an inert substance, called placebo (ex: flour)
Validity requires 3 conditions
For a clinical study to be valid, 3 conditions need to be met:
1. The item or product to be tested requires a control or inert substance (placebo), without knowing which is which.
2. A random distribution of the studied product (randomization)
3. There is a period of time necessary to test the effect of the product.
The participants are not allowed to know
Participants in clinical research should not know if they take the dry pea or the inert product. The same principle applies to researchers and research staff. The results are known only at the end of the study.
Then this dry pea… does it work or not?
Let’s go back to our example. You accept to participate to the clinical study. You are assigned to either take the dry pea or the placebo by randomization. The placebo looks exactly like the dry pea, but it’s made of flour. Neither you nor the researcher knows in which group you are. You take it once a day throughout the study period. Your cholesterol level is measured at the beginning and at the end date of the study.
At the end, we compare the blood cholesterol level of the two groups. Statistical calculations show that eating a dry pea once a day does not confer any advantage in the reduction of cholesterol level in comparison with the placebo.
Two important aspects
Let’s have a look at two important points:
- Advantageous reduction
- Statistical calculation
It is possible to note an equivalent effect on cholesterol in the two groups (pea and placebo). Why? It is the placebo effect. It is simply the effect of taking a medication, active or not.
The placebo effect
If you give me a tablet of flour and you tell me that it is a sleeping pill, it is very possible that I sleep better just because I believe you and my brain reacts to your statements. We can notice the placebo effect in approximately 30% of the cases. Odd isn't it?
It is also known that the color of the tablets can add to the placebo effect
An advantageous reduction would be a clear reduction of cholesterol levels caused by the daily intake of the dry pea in comparison with the placebo.
Group comparison and hypothesis analysis are done by statistical calculation. It is important to check that the two groups in comparison are similar, so that the observed difference is attributed to the dry pea effect and not to a baseline difference between groups.
The effect of Chance
Statistical calculations are important to confirm that the differences observed are not related to the effect of chance. By convention, the calculated effect of chance should be less than 5%.
Effect of certainty
Statistical calculation allows the confirmation of the results of a study, provided that a sufficient number of subjects were participating in the study and that they were followed up for an adequate period of time.
Once the study is completed, we can tell the participants in which group (drug or placebo) they were and reveal the results of the study.
What is your implication?
Major advances in modern medicine were achieved thanks to research and to patients like you who agree to take part in a research project. Your agreement is essential. It is impossible to take part in a study without your agreement. You receive explanations about the purpose of the study, the hypothesis to be tested, the potential benefits, the possible side effects and the impact of your implication (blood tests, medical visits, phone calls, etc). You must also sign a consent form. Your participation can be revoked at any time and this, without any consequence on the quality of the care you will receive.
When you participate in a clinical study, a team of nurses is available at any time to answer your questions.
Clinical research is not about using people as mice or guinea pigs. Several stages and safety steps have already been achieved when your doctor or his team asks you to take part in a research project.
Every clinical study has to be approved by Health Canada, the authority which supervises the safety of new drugs or devices.
Another example: Coumadin
Another example is the recent development of new oral anticoagulants, to prevent clot formation in patients with atrial fibrillation. Clot formation is our major concern among these patients. It may form in the atrium, and be released into the blood circulation. If it reaches the brain, it could cause a stroke. It could also embolize elsewhere in the body and cause significant damage to the affected organs.
For decades, coumadin (warfarin) was the only available “blood thinner”. Coumadin is a drug that requires a constant monitoring (blood tests) to adjust the dosage. It has also many possible interactions with food and drugs. Moreover, a certain blood level needs to be achieved for the drug to be effective and to avoid clot formation (it is called the therapeutic range). If a patient is above this range, the blood is too “thin” and the risk of bleeding increases. On the other hand, if a patient is below that range, the blood is too “thick” and the risk of clot formation and embolization increases.
Over the last few years, research in this field has led to the development of better anticoagulant agents. In comparison with coumadin, these new drugs have little or no food interaction and little drug interactions. Doses are fixed (according to patient age and renal function) and do not need to be constantly monitored by blood tests. These agents are now considered better than coumadin for the prevention of clot formation in patients with atrial fibrillation.
Several recent advances in cardiology
Over the last twenty years, we have witnessed major advances in the field of cardiology, thanks to all those patients who accepted to participate in various clinical studies. Patients with cardiovascular diseases now live better and longer.
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