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A clinical control group is a group of individuals, involved in a healthcare experimentation, who do not receive the treatment, in order to determine the effectiveness of the drug, supplement or treatment being tested.
Comparing the results of a group receiving treatment with the clinical control group is essential to help rule out imagined or random effects of the treatment. In the United States, the Food and Drug Administration (FDA) provides some guidelines about how the groups should be selected; in general the control group and the group receiving the treatment should be as identical as possible.
If a drug is being tested, the control group will frequently be given a placebo. This is done as a double blind test, as neither the healthcare professional nor the patient know if they are receiving the drug under test or a placebo, and don't find out which substance was administered until after the experiment is concluded.
A clinical control group can be a placebo arm or it can involve an old method used to address a clinical outcome when testing a new idea. For example in a study released by the British Medical Journal, in 1995 studying the effects of strict blood pressure control versus more relaxed blood pressure control in diabetic patients, the clinical control group was the diabetic patients that did not receive tight blood pressure control. In order to qualify for the study, the patients had to meet the inclusion criteria and not match the exclusion criteria. Once the study population was determined, the patients were placed in either the experimental group (strict blood pressure control <150/80mmHg) versus non strict blood pressure control (<180/110). There were a wide variety of ending points for patients such as death, myocardial infarction, stroke, etc. The study was stopped before completion because strict blood pressure control was so much superior to the clinical control group which had relaxed blood pressure control. The study was no longer considered ethical because tight blood pressure control was so much more effective at preventing end points that the clinical control group had to be discontinued. The clinical control group is not always a placebo group. Sometimes the clinical control group can involve comparing a new drug to an older drug in a superiority trial. In a superiority trial, the clinical control group is the older medication rather than the new medication. For example in the ALLHAT trial, Thiazide diuretics were demonstrated to be superior to calcium channel blockers or angiotensin converting enzyme inhibitors in reducing cardiovascular events in high risk patients with hypertension. In the ALLHAT study, the clinical control group was not a placebo it was ACEI or Calcium Channel Blockers. Overall, clinical control groups can either be a placebo or an old standard of therapy.