Control Group: From 1 Different Sources
A group of participants that serves as the basis of comparison when assessing the effects of the intervention of interest that is given to the participants in the treatment group. Depending upon the circumstances of the trial, a control group may receive no treatment, a ‘usual’ or ‘standard’ treatment, or a placebo. To make the comparison valid, the composition of the control group should resemble that of the treatment group as closely as possible.
A study that starts with the identification of persons with the disease (or other outcome variable) of interest, and a suitable control (comparison, reference) group of persons without the disease. The relationship of an attribute to the disease is examined by comparing the diseased and non-diseased with regard to how frequently the attribute is present or, if quantitative, the level of the attribute, in each of the groups.... case control study
See CONTRACEPTION.... birth control
Psychotherapy in which at least two, but more commonly up to ten, patients, as well as the therapist, take part. The therapist encourages the patients to analyse their own and the others’ emotional and psychological diffculties. Group therapy is also used to help patients sharing the same condition – for instance, alcoholism or compulsive gambling. They discuss their problems for perhaps an hour twice a week and explore ways of resolving them.... group therapy
See BLOOD GROUPS.... abo blood groups
People are divided into four main groups in respect of a certain reaction of the blood. This depends upon the capacity of the serum of one person’s blood to cause the red cells of another’s to stick together (agglutinate). The reaction depends on antigens (see ANTIGEN), known as agglutinogens, in the erythrocytes and on ANTIBODIES, known as agglutinins, in the serum. There are two of each, the agglutinogens being known as A and B. A person’s erythrocytes may have (1) no agglutinogens, (2) agglutinogen A, (3) agglutinogen B, (4) agglutinogens A and B: these are the four groups. Since the identi?cation of the ABO and Rhesus factors (see below), around 400 other antigens have been discovered, but they cause few problems over transfusions.
In blood transfusion, the person giving and the person receiving the blood must belong to the same blood group, or a dangerous reaction will take place from the agglutination that occurs when blood of a di?erent group is present. One exception is that group O Rhesus-negative blood can be used in an emergency for anybody.
| Agglutinogens | Agglutinins | Frequency |
| in the | in the | in Great |
| Group | erythrocytes | plasma | Britain |
| AB | A and B | None | 2 per cent |
| A | A | Anti-B | 46 per cent |
| B | B | Anti-A | 8 per cent |
| O | Neither | Anti-A and | 44 per cent |
| A nor B | Anti-B | |
| | | |
Rhesus factor In addition to the A and B agglutinogens (or antigens), there is another one known as the Rhesus (or Rh) factor – so named because there is a similar antigen in the red blood corpuscles of the Rhesus monkey. About 84 per cent of the population have this Rh factor in their blood and are therefore known as ‘Rh-positive’. The remaining 16 per cent who do not possess the factor are known as ‘Rh-negative’.
The practical importance of the Rh factor is that, unlike the A and B agglutinogens, there are no naturally occurring Rh antibodies. However, such antibodies may develop in a Rh-negative person if the Rh antigen is introduced into his or her circulation. This can occur (a) if a Rh-negative person is given a transfusion of Rh-positive blood, and (b) if a Rh-negative mother married to a Rh-positive husband becomes pregnant and the fetus is Rh-positive. If the latter happens, the mother develops Rh antibodies which can pass into the fetal circulation, where they react with the baby’s Rh antigen and cause HAEMOLYTIC DISEASE of the fetus and newborn. This means that, untreated, the child may be stillborn or become jaundiced shortly after birth.
As about one in six expectant mothers is Rh-negative, a blood-group examination is now considered an essential part of the antenatal examination of a pregnant woman. All such Rh-negative expectant mothers are now given a ‘Rhesus card’ showing that they belong to the rhesus-negative blood group. This card should always be carried with them. Rh-positive blood should never be transfused to a Rh-negative girl or woman.... blood groups
A formal association of three or more health practitioners or other health professionals providing health services. Income from the practice is pooled and redistributed to the members of the group according to some prearranged plan.... group practice
The group of persons for whom an intervention is planned. For example, the targeting of services to particular user groups.... targeting / target population / target group
Use of natural, indigenous predators or organisms to control medically important insects.... biological control
The set of actions taken to ensure that spending is in line with budgeted amounts and the regulations for spending them.... budgetary control
A category in a classification or typology of clients. Clients can be classified in various dimensions, e.g. by dependency level, by diagnosis.... client group
A control group that is observed by investigators at the same time as the treatment group but that was not established using random assignment of participants to control and treatment groups. Differences in the composition of the treatment and control groups may result.... concurrent nonrandomized control
A system used for payment under prospective payment systems. It classifies treatments by diagnosis, measuring the relative complexity of a hospital procedure and accounting for the resources used in the procedure. The system accounts for principal diagnosis, secondary diagnosis, surgical procedures, age, sex and presence of complications.... diagnosis-related group
The control of disease caused by infectious agents or their toxic products. Successes in the 19th and 20th centuries in the treatment and control of communicable diseases such as SMALLPOX, CHOLERA, TUBERCULOSIS, gastrointestinal infections, POLIOMYELITIS and SEXUALLY TRANSMITTED DISEASES (STDS) resulted in an erroneous conception that they no longer posed a serious threat to public health, and certainly not in developed countries. As a consequence, the maintenance of e?ective public health strategies steadily lost out in the competition for resources to the more ‘glamorous’ developments in medicine, such as improved CANCER treatments, HEART surgery, kidney DIALYSIS and organ TRANSPLANTATION. However, in recent decades the dangers of this approach have become increasingly apparent. Rapidly expanding urban populations, more complex lifestyles, new and resurgent infections (some linked to a spread of antibiotic resistance) such as AIDS/HIV and variant CREUTZFELDT-JAKOB DISEASE (CJD), and the ease with which infection can be spread by the enormous growth of long-distance travel and population migrations are severely straining existing public health measures. The supply of clean water, e?ective waste- and sewage-disposal measures, the hygienic production and delivery of food and early detection and subsequent prevention of infectious diseases can no longer be taken for granted. Governments will need to strengthen the provision of workable, properly resourced public health facilities, and developing countries will need ?nancial support and expert help from developed nations to achieve this objective. Timely recognition of new and resurgent infectious diseases requires national and international early-warning mechanisms to ensure rapid investigation and implementation of e?ective control measures. Otherwise, serious breakdowns in public health will occur, and international co-operation is vital to provide and support control measures. (See also COMMUNICABLE DISEASE; NOTIFIABLE DISEASES.)... communicable diseases control
1 Represents classes of hospital patients with similar clinical characteristics. DRGs form a clinical grouping system which describes hospital discharges according to medical condition. 2 A system used for payment under prospective payment systems. It classifies treatments by diagnosis, measuring the relative complexity of a hospital procedure and accounting for the resources used in the procedure. The system accounts for principal diagnosis, secondary diagnosis, surgical procedures, age, sex and presence of complications.... diagnosis-related group (drg)
All the measures designed to prevent or reduce as much as possible the incidence, prevalence and consequences of disease, such as the control of disease vectors, the removal or reduction of the influence of predisposing factors in the environment, immunization and curative care.... disease control
A type of group discussion that is designed to elicit information about the wants, needs, viewpoints, beliefs and experiences of the intended audience. Focus groups can aid in better understanding the expressions and terminology commonly used by people in the audience, as well as their attitudes and beliefs about health care. They are useful for helping uncover the reasons behind people’s responses.... focus group
A house in which people have their own rooms but there are communal facilities. Staff may live in to offer support.... group home
See “assisted living facility”.... group senior assisted housing
A combination of biological and insecticidal methods of control, e.g. the introduction of predacious fish to breeding places which are also sprayed with insecticides that have minimum effect on the fish.... integrated control
An executive agency of the Department of Health with the prime function of safeguarding the public health. It ensures that branded and non-branded MEDICINES on the UK market meet appropriate standards of safety, quality and e?cacy. The agency applies the strict standards set by the UK Medicines Act (1968) and relevant European Community legislation.... medicines control agency
People who share a cultural heritage which is different from the majority ethnic culture. See also “ethnicity”; “culture”.... minority ethnic group
A National Health Service body intended to combat the increasing threat from infectious diseases and biological, chemical and radiological hazards. Covering England, the agency includes the Public Health Laboratory Service, the National Radiological Protection Board, the Centre for Applied Microbiology and Research, and the National Focus Group for Chemical Incidents.... national infection control and health protection agency
A face-to-face group judgement technique in which participants generate silently, in writing, responses to a given question/problem; responses are collected and posted, but not identified by author, for all to see; responses are openly clarified, often in a round robin format; further iterations may follow; and a final set of responses is established by voting/ranking.... nominal group technique
The sum of all the activities which prevent unwanted change in quality. In the health care setting, quality control requires a repeated series of feedback loops which monitor and evaluate the care of the individual (and other elements in the health care process). These feedback loops involve checking the care being delivered against standards of care, identification of any problems or opportunities for improvement, and prompt corrective action, so that the quality is maintained.... quality control (qc)
A process within society which both formally, through law, and informally, through customs, norms and mores, attempts to influence and order the actions of social groups and their members and thus maintain public order.... social control
Any set of persons within society with particular demographic, economic or social characteristics.... social group
A group of people who share a common bond (e.g. caregivers, patients, families of patients) who come together on a regular basis to share problems and experiences or keep in contact in other ways (e.g. the Internet).... support group
Blood group of people donor can receive blood from... donor’s blood group
(CCGs) self-governing bodies set up by the Health and Social Care Act 2012, following the abolition of *primary care trusts and *strategic health authorities, to commission most NHS services in England. CCGs are formed of all GP practices within a given geographical area, and all GP practices must belong to a clinical commissioning group. All CCGs have their own constitution and governing body, which (in addition to GPs) must include at least one registered nurse and at least one secondary care specialist doctor. There are currently 195 CCGs in England.... clinical commissioning groups
the control of disease due to infectious agents or their toxic products. See Consultant in Health Protection.... communicable disease control
(in Britain) any of the groups that work with NHS foundation trusts to represent the views of patients and other interested parties in setting the strategic direction of the trust. They are often formed around specific disease categories or patient groups (e.g. deaf patients, children in care).... community interest group
(GBS) a Gram-positive bacterium that causes life-threatening infections in newborn infants following vaginal delivery (see Streptococcus; Lancefield classification). 20% of pregnant women are carriers and have no symptoms; however, *vertical transmission of the bacterium from mother to fetus at the time of delivery may lead to neonatal sepsis, characterized by pneumonia, meningitis, and death in some cases. Antibiotic prophylaxis with penicillin during labour is recommended for women with risk factors or who are known to be carriers.... group b streptococcus
see National Statistics Socio-economic Classification.... socio-economic group
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