Page 704 - 16Neonatal Jaundice_compressed

Neonatal jaundice

Cochrane Collaboration An international organisation in which people find, appraise and
review specific types of studies called randomised controlled trials.
The Cochrane Database of Systematic Reviews contains regularly
updated reviews on a variety of health issues and is available
electronically as part of the Cochrane Library.
Cochrane Library The Cochrane Library consists of a regularly updated collection of
evidence-based medicine databases including the Cochrane Database
of Systematic Reviews (reviews of randomised controlled trials
prepared by the Cochrane Collaboration). The Cochrane Library is
available on CD-ROM and the Internet.
Cohort A group of people sharing some common characteristic (e.g. patients
with the same disease), followed up in a research study for a
specified period of time.
Cohort study An observational study that takes a group (cohort) of patients and
follows their progress over time in order to measure outcomes such
as disease or mortality rates and make comparisons according to the
treatments or interventions that patients received. Thus within the
study group, subgroups of patients are identified (from information
collected about patients) and these groups are compared with respect
to outcome, e.g. comparing mortality between one group that
received a specific treatment and one group which did not (or
between two groups that received different levels of treatment).
Cohorts can be assembled in the present and followed into the future
(a ‘concurrent’ or ‘prospective’ cohort study) or identified from past
records and followed forward from that time up to the present (a
‘historical’ or ‘retrospective’ cohort study). Because patients are not
randomly allocated to subgroups, these subgroups may be quite
different in their characteristics and some adjustment must be made
when analysing the results to ensure that the comparison between
groups is as fair as possible.
Combined modality Use of different treatments in combination (for example surgery,
chemotherapy and radiotherapy used together for cancer patients).
Co-morbidity Co-existence of a disease or diseases in the people being studied in
addition to the health problem that is the subject of the study.
Confidence interval A way of expressing certainty about the findings from a study or
group of studies, using statistical techniques. A confidence interval
describes a range of possible effects (of a treatment or intervention)
that are consistent with the results of a study or group of studies. A
wide confidence interval indicates a lack of certainty or precision
about the true size of the clinical effect and is seen in studies with too
few patients. Where confidence intervals are narrow they indicate
more precise estimates of effects and a larger sample of patients
studied. It is usual to interpret a ‘95%’ confidence interval as the
range of effects within which we are 95% confident that the true
effect lies.
Confounder or confounding factor Something that influences a study and can contribute to misleading
findings if it is not understood or appropriately dealt with. For
example, if a group of people exercising regularly and a group of
people who do not exercise have an important age difference then
any difference found in outcomes about heart disease could well be
due to one group being older than the other rather than due to the
exercising. Age is the confounding factor here and the effect of
exercising on heart disease cannot be assessed without adjusting for
age differences in some way.

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