BMI2602 – EXAM PREPARATION
DOCUMENT
@SCIENCERA
,QUESTION 1
Define the following terms:
1.1 Endemic
Endemic refers to the habitual presence of a disease within a geographic given area.
1.2 Incubation period
The incubation period is the time interval from the receipt of infection to the time of clinical illness.
1.3 Misclassification bias
Misclassification bias is a type of bias that arises from a measurement error e.g. a study participant could
be categorized in an incorrect category hence altering the results of a study.
1.4 Retrospective cohort
A retrospective cohort is a historic cohort as it uses historical data of participants who already have the
condition of interest, then try to determine why they have the condition e.g. do the people that have lung
cancer now develop it because they smoked in their teenage hood
1.5 Positive predictive value
A positive predictive value shows the proportion of patients who test positive for a disease and turn out
to have the disease. It is all the non-false positive tests.
QUESTION 2
Give short explanatory notes of the following:
2.1 Prospective cohort study
A prospective cohort study takes a group of similar people and observes them over a period of time. The
investigator identifies the original population at the beginning of the study then observes them until the
disease develops or does not develop for example the investigator may observe children from
kindergarten into their teenage age whether or not they decide to smoke then observe who gets lung
cancer or does not.
2.2 Relationship between validity and reliability
Validity distinguishes between who has the condition of interest and who does not, reliability focuses on
the overall consistency of a measure. Reliability is necessary for validity; however, it is not sufficient,
even though we may get a test to be completely reliable it’s possible for that measure to be invalid.
2.3 Ethical issues
,The Ethical issues facing epidemiology reflects on an epidemiologist’s obligation to participate in
epidemiological and clinical studies, as well as the challenges resulting from the major position that the
discipline occupies at the interface of science and public policy. Most issues arising are often complex
and have no simple answer. There is a need for patient consent, protection of privacy and confidentiality
of family members
2.4 Public health
Public health is defined as the health of a population as a whole, it is normally monitored, regulated and
controlled by the state. It is basically a science of improving the health of the people and the community.
2.5 Sequential testing
Sequential testing is a form of a 2 stage testing whereby in the first stage less invasive tests are
performed to screen a certain object of interest, those that test positive are recalled for further more
invasive testing, yielding greater specificity and sensitivity. The hope of this is to reduce false positives.
QUESTION 3
Describe the four levels of prevention. Give examples of action at each level which would be
appropriate as part of a comprehensive program to prevent stroke. [20]
Prevention may be defined as the action aimed at eradicating, minimizing or eliminating the impact of
disease and disability; there are 4 levels of prevention which are:
1. Primordial prevention- it is the prevention of the emergence or development of risk factors in
countries or population groups in which they have not yet appeared. A comprehensive programme aimed
at preventing stroke on this level would encourage children to avoid eating a lot of sugar and bad fats as
these are the factors that may lead to a stroke.
2. Primary prevention- the action taken before the onset of disease which removes the possibility that
the disease may occur, it may be accomplished by measures of health promotion or specific protection.in
a stroke prevention program this would be achieved by a population mass strategy which is a strategy
directed to the entire population, for example try and reduce the serum cholesterol of a population by
mass producing omega 3 rich foods only , hence majority of people would have low cholesterol level
which might lower the chances of getting a stroke. A high risk strategy may be employed here as well
whereby individuals at special risk are then individualized and assisted with methods like medications to
prevent them from getting a stroke.
3. Secondary prevention- it involves identifying the people who have the disease but show no clinical
signs , and stopping the disease before complications arise.in a stroke prevention programme at this
level medical care is given to the patient with stroke , physiotherapy is enhanced to reduce the effects of
stroke and blood pressure management is crucial at this stage. Antithrombotic management is also key
here.
, 4. Tertiary prevention- is used when the disease process has advanced beyond its early stages. It may
be defined as all the measures available to reduce or limit impairments and disabilities and to promote
the patients’ adjustments to irremediable conditions. A stroke program at this level tries to lessen
disability limitation and rehabilitations; physiotherapy is the very important at this stage. They could
also help stroke patients by providing social support by taking care of them, and helping them manage
day to day.
QUESTION 4
Evidence-based guidelines have improved clinical outcomes. Elaborate. [20]
Evidence based guidelines in epidemiology and medicine take a systemic approach to clinical treatment
by combining the highest quality evidence with expert medical consensus in order to form guidelines for
patient care. These guidelines improve clinical outcomes and patient care.
The guidelines manage to improve clinical outcomes through the methodology with which they are
formulated and this methodology follows a very organized step process, which involves
1. Formulating a good clinical question-a question is formulated based on a diagnosis, test or procedure;
better questions tend to lead to best search results.
2. Search for evidence-an extensive literature review is performed to find strategies, the best strategies
are chosen based on the clinical questions formulated.
3. Critically appraise the evidence-not all research is created equal, there is a hierarchy of evidence, so
one needs to use qualitative and quantitative findings and appraise the results for validity, reliability
applicability, bias, strength and magnitude.
4. Implement the evidence- an assessment of the healthcare professionals’ level of experience and
expertise is done. A plan to educate the staff involved in the practice change is developed, and then a
criteria to measure clinical outcome is then developed.
5. An evaluation of the practice changes and patient outcome is then performed by measuring the
outcome data and analyzing it. Questions such as “did the practice change improve patient outcomes?”
are asked.
6. Improve global health through evidence dissemination- evidence based guidelines are then published
through peer-reviewed guidelines
This thorough process of establishing these guidelines make it a highly conducive methodology that
often tends to indicate that randomized trials focusing on evidence obtained often improve clinical
outcomes. When more physicians implement these established guidelines, more evidence of clinical
outcome being positive is established.
DOCUMENT
@SCIENCERA
,QUESTION 1
Define the following terms:
1.1 Endemic
Endemic refers to the habitual presence of a disease within a geographic given area.
1.2 Incubation period
The incubation period is the time interval from the receipt of infection to the time of clinical illness.
1.3 Misclassification bias
Misclassification bias is a type of bias that arises from a measurement error e.g. a study participant could
be categorized in an incorrect category hence altering the results of a study.
1.4 Retrospective cohort
A retrospective cohort is a historic cohort as it uses historical data of participants who already have the
condition of interest, then try to determine why they have the condition e.g. do the people that have lung
cancer now develop it because they smoked in their teenage hood
1.5 Positive predictive value
A positive predictive value shows the proportion of patients who test positive for a disease and turn out
to have the disease. It is all the non-false positive tests.
QUESTION 2
Give short explanatory notes of the following:
2.1 Prospective cohort study
A prospective cohort study takes a group of similar people and observes them over a period of time. The
investigator identifies the original population at the beginning of the study then observes them until the
disease develops or does not develop for example the investigator may observe children from
kindergarten into their teenage age whether or not they decide to smoke then observe who gets lung
cancer or does not.
2.2 Relationship between validity and reliability
Validity distinguishes between who has the condition of interest and who does not, reliability focuses on
the overall consistency of a measure. Reliability is necessary for validity; however, it is not sufficient,
even though we may get a test to be completely reliable it’s possible for that measure to be invalid.
2.3 Ethical issues
,The Ethical issues facing epidemiology reflects on an epidemiologist’s obligation to participate in
epidemiological and clinical studies, as well as the challenges resulting from the major position that the
discipline occupies at the interface of science and public policy. Most issues arising are often complex
and have no simple answer. There is a need for patient consent, protection of privacy and confidentiality
of family members
2.4 Public health
Public health is defined as the health of a population as a whole, it is normally monitored, regulated and
controlled by the state. It is basically a science of improving the health of the people and the community.
2.5 Sequential testing
Sequential testing is a form of a 2 stage testing whereby in the first stage less invasive tests are
performed to screen a certain object of interest, those that test positive are recalled for further more
invasive testing, yielding greater specificity and sensitivity. The hope of this is to reduce false positives.
QUESTION 3
Describe the four levels of prevention. Give examples of action at each level which would be
appropriate as part of a comprehensive program to prevent stroke. [20]
Prevention may be defined as the action aimed at eradicating, minimizing or eliminating the impact of
disease and disability; there are 4 levels of prevention which are:
1. Primordial prevention- it is the prevention of the emergence or development of risk factors in
countries or population groups in which they have not yet appeared. A comprehensive programme aimed
at preventing stroke on this level would encourage children to avoid eating a lot of sugar and bad fats as
these are the factors that may lead to a stroke.
2. Primary prevention- the action taken before the onset of disease which removes the possibility that
the disease may occur, it may be accomplished by measures of health promotion or specific protection.in
a stroke prevention program this would be achieved by a population mass strategy which is a strategy
directed to the entire population, for example try and reduce the serum cholesterol of a population by
mass producing omega 3 rich foods only , hence majority of people would have low cholesterol level
which might lower the chances of getting a stroke. A high risk strategy may be employed here as well
whereby individuals at special risk are then individualized and assisted with methods like medications to
prevent them from getting a stroke.
3. Secondary prevention- it involves identifying the people who have the disease but show no clinical
signs , and stopping the disease before complications arise.in a stroke prevention programme at this
level medical care is given to the patient with stroke , physiotherapy is enhanced to reduce the effects of
stroke and blood pressure management is crucial at this stage. Antithrombotic management is also key
here.
, 4. Tertiary prevention- is used when the disease process has advanced beyond its early stages. It may
be defined as all the measures available to reduce or limit impairments and disabilities and to promote
the patients’ adjustments to irremediable conditions. A stroke program at this level tries to lessen
disability limitation and rehabilitations; physiotherapy is the very important at this stage. They could
also help stroke patients by providing social support by taking care of them, and helping them manage
day to day.
QUESTION 4
Evidence-based guidelines have improved clinical outcomes. Elaborate. [20]
Evidence based guidelines in epidemiology and medicine take a systemic approach to clinical treatment
by combining the highest quality evidence with expert medical consensus in order to form guidelines for
patient care. These guidelines improve clinical outcomes and patient care.
The guidelines manage to improve clinical outcomes through the methodology with which they are
formulated and this methodology follows a very organized step process, which involves
1. Formulating a good clinical question-a question is formulated based on a diagnosis, test or procedure;
better questions tend to lead to best search results.
2. Search for evidence-an extensive literature review is performed to find strategies, the best strategies
are chosen based on the clinical questions formulated.
3. Critically appraise the evidence-not all research is created equal, there is a hierarchy of evidence, so
one needs to use qualitative and quantitative findings and appraise the results for validity, reliability
applicability, bias, strength and magnitude.
4. Implement the evidence- an assessment of the healthcare professionals’ level of experience and
expertise is done. A plan to educate the staff involved in the practice change is developed, and then a
criteria to measure clinical outcome is then developed.
5. An evaluation of the practice changes and patient outcome is then performed by measuring the
outcome data and analyzing it. Questions such as “did the practice change improve patient outcomes?”
are asked.
6. Improve global health through evidence dissemination- evidence based guidelines are then published
through peer-reviewed guidelines
This thorough process of establishing these guidelines make it a highly conducive methodology that
often tends to indicate that randomized trials focusing on evidence obtained often improve clinical
outcomes. When more physicians implement these established guidelines, more evidence of clinical
outcome being positive is established.
