M U H A M M A D S A L M A N
L E C T U R E R
P U N J A B U N I V E R S I T Y C O L L E G E O F
P H A R M A C Y
Health System Research (HSR)
Research?
 Research simply seeks the answer of certain
questions which have not been answered so far and
the answers depend upon human efforts
 Example of the moon
 Some years ago man did not know what exactly the
moon is?
 Was this problem which had no solution?
 Man could only make some assumptions about it but
the man know this time by his efforts, he went to the
moon brought the soil of the moon and studied it
 The man is now able to give concrete answer of the
problem what is the moon?
 Now the question arises
 “Is the answer of the question in examination also
research”?
 The answer is ‘no’, because the answers of these
questions are available (text-books, class-notes etc)
 Research answers only those questions of which the
answers are not available in literature i.e., in human
knowledge
 Therefore, we can say research seeks the answer only of those
questions of which the answers can be given on the basis of
available facilities
 Research is simply the process of arriving as dependable
solution to a problem through the planned and systematic
collection, analysis and interpretation of data
 It is the most important process for advancing knowledge for
promoting progress
 Also enables man to relate more effectively to his environment
to accomplish his purpose and to resolve his conflicts
Term “Research”
 Therefore, research means to observe the
phenomena again and again from different
dimensions
 “Research is a systematized effort to gain new
knowledge.” (V. Redman and A.V.H. Mory)
 “Research is an honest exhaustive, intelligent
searching for facts and their meanings or
implications with reference to a given problem. The
product or findings of a given piece of research
should be an authentic, verifiable and contribution
to knowledge in the field studied.” (P.M. Cook)
 He emphasized the following characteristics of
research in his definition:
 It is an honest and exhaustive process.
 The facts are studied with understanding.
 The facts are discovered in the light of problem. Research is
problem-centred.
 The findings are valid and verifiable.
 Research work should contribute new knowledge in that field
Objectives of research
 Theoretical objective
 Formulate the new theories, principles or laws.
 Such type of research is explanatory because it explains the
relationship of certain variables.
 These researches contribute some basic knowledge to the
human knowledge.
 The researches in different disciplines such ads physics,
chemistry, mathematics etc. have theoretical objective.
 Factual objective
 Researches whose objective is factual find out new facts
 This objective is by nature descriptive
 Application objective
 Research having application objective does not contribute a
new knowledge in the fund of human knowledge but suggests
new applications. By application we mean improvement and
modification in practice.
 For example if anyone gives a new application of electricity
then such type of research has application objective
General characteristics of research
 Gathers new knowledge or data from primary or first –hand sources
 Places emphasis upon the discovery of general principles
 An exact systematic and accurate investigation
 Uses certain valid data gathering devices
 Logical and objective
 Researcher resists the temptation to seek only the data that support
his/her hypotheses
 Researcher eliminates personal feelings and preferences
 Endeavors to organize data in quantitative terms
 Patient and unhurried activity
 Researcher is willing to follow his/her procedures to the conclusions
that may be unpopular and bring social disapproval
 Research is carefully recorded and reported conclusions and
generalizations are arrived at carefully and cautiously
 Health research → A systematic collection, analysis and
interpretation of health and health-related data to answer a
certain question or to solve a problem
 Health systems research also known as health services
research or health policy and systems research
 Health systems research → "The people, institutions, and
activities whose primary purpose is to generate high quality
knowledge that can be used to promote, restore, and or
maintain the health status of populations. It can include the
mechanisms adopted to encourage the utilization of research.“
(HRSA, WHO)
Classification of Research
 Basic level
 It is designed to add an organized body of scientific knowledge
and does not necessarily produce results of immediate
practical value
 Applied level
 Applied research is undertaken to solve an immediate practical
problem and the goal of adding to scientific knowledge is
secondary
Kinds of research
 There are various bases to classify the research
 On the basis of objective of the research
 Fundamental research
 Action research
 On the basis of approach of the research
 Longitudinal research
 Cross sectional research
 On the basis of precision in research findings
 Experimental research
 Non experimental research
 On the basis of nature of findings
 Explanatory research
 Descriptive research
 According to national science foundation
 Basic research: Those researches which embrace origin or
unique investigation for the advancement of knowledge
 Applied research: which may be characterized as utilization in
practice
 Developmental research: use of scientific knowledge for the
production of useful materials, devices, systems, methods for
processes excluding design and production engineering.
Health research triangle
 three operational interlinked categories of biomedical, health services and behavioral
research, the so-called health research triangle
Bio-medical Behavioral
Health services
Research process
 Selection of Research problem
 Formulation of hypothesis
 Research plan
 Data collection
 Analysis of data
 Formulation of result and conclusions
Selection and formulation of the problem
?
Hypothesis
 Carefully constructed statements about a
phenomenon in the population
 Generated by deductive reasoning, or based on
inductive reasoning from prior observations
 One of the most useful tools of health research is the
generation of hypotheses which, when tested, will
lead to the identification of the most likely causes of
disease or changes in the condition being observed
 Mill’s canons of inductive reasoning are frequently
utilized in the forming of hypotheses which relate
association and causation.
 Method of difference - when the frequency of a
disease is markedly dissimilar under two
circumstances, and a factor can be identified in one
circumstance and not the other, this factor, or its
absence, may be the cause of the disease
 for example → the difference in frequency of lung
cancer in smokers and nonsmokers
 Method of agreement - if a factor, or its absence is
common to a number of different circumstances that
are found to be associated with the presence of a
disease, that factor, or its absence may be causally
associated with the disease
 The occurrence of hepatitis A is associated with
patient contact, poor sanitation and hygiene, each
conducive to the transmission of the hepatitis virus
 Method of concomitant variation, or the dose response
effect
 The increasing expression of endemic goiter with
decreasing levels of iodine in the diet
 The increasing frequency of leukemia with increasing
radiation exposure
 The increase in prevalence of elephantiasis in areas of
increasing filarial endemicity
 Method of analogy – the distribution and frequency
of a disease or effect may be similar enough to that of
some other disease to suggest commonality in cause
 e.g. hepatitis B virus infection and cancer of the liver
Research plan/design
 Defining the population, characteristics of interest
and probability distributions
 Type of study
 observational or experimental
 method of data collection, management and analysis:
 sample selection
 measuring instruments (reliability and validity of instruments)
 training of interviewers
 quality control of measurements
 computerization, checking and validating measurements
 the issue of missing observations
 statistical summarization of information
 testing of hypothesis
 ethical considerations
 Conclusions
 Deductive Reasoning
 Thinking precedes from general assumption to specific
application
GENERAL → SPECIFIC
 Inductive reasoning
 Conclusions about events are based on information generated
through many individual and direct observations
SPECIFIC → GENERAL
Inductive reasoning Deductive reasoning
SPECIFIC → GENERAL GENERAL → SPECIFIC
Every rabbit has been observed has
lungs. Therefore, every rabbit has lungs
Every mammal has lungs. All rabbits
are mammals. Therefore, every rabbit
has lungs.
Epidemiological studies
Classification
 Non-international
 AKA observational studies
 Researchers do not manipulate situations/objects
 Only describes or analyses situations/objects
 Interventional
 Participants are assigned to receive one or more interventions
(or no intervention) so that researchers can evaluate the effects
of the interventions on biomedical or health-related outcomes.
Non-interventional studies
 Descriptive studies
 Case series
 Community diagnosis or need assessment
 Epidemiological description of disease occurrence
 Descriptive cross-sectional studies
 Ecological descriptive studies
 Analytical studies
 Case-control studies
 Cohort studies
 Prospective cohort studies
 Retrospective cohort studies
 Analytical cross-sectional studies
Descriptive studies
 When an epidemiological study is not structured
formally as an analytical or experimental study i.e.
when it is not aimed specifically to test a hypothesis,
it is called a descriptive study
 The wealth of material obtained in most descriptive
studies allows the generation of hypotheses, which
can then be tested by analytical or experimental
designs
 Case series
 based on reports of a series of cases of a specific condition, or a
series of treated cases, with no specifically allocated control
group
 These represent the numerator of disease occurrence, and
should not be used to estimate risks
 Community diagnosis or needs assessment
 This kind of study entails collection of data on
 existing health problems
 Programs
 Achievements
 Constraints
 social stratification
 leadership patterns
 focal points of resistance or high prevalence, or groups at highest
risk.
 Its purpose is to identify existing needs and to provide baseline
data for the design of further studies or action
 Epidemiological description of the disease occurrence
 This common use of the descriptive approach involves the collection of
data on the occurrence and distribution of disease in populations
according to
 specific characteristics of individuals
 Age
 Sex
 Education
 Smoking habits
 Religion
 Occupation
 social class
 Marital status
 Health status
 Personality
 Place (rural/urban, local, national, international)
 Time (epidemic, seasonal, cyclic, secular)
 Descriptive cross-sectional studies
 AKA population/community surveys
 Entail the collection of data on, as the term implies, a cross-section
of the population, which may comprise the whole population or a
proportion (sample) of it
 Many cross-sectional studies do not aim at testing a hypothesis about
an association
 Provide a prevalence rate at a particular point in time → point
prevalence
 Or over a period of time → period prevalence
 Ecological descriptive studies
 When the unit of observation is an aggregate (e.g. family, clan
or school)
 Or an ecological unit (a village, town or country) the study
becomes an ecological descriptive study
Analytical strategies of epidemiological studies
 Observational studies, where establishing a relationship
between a ‘risk factor’ (etiological agent) and an outcome
(disease) is the primary goal, are termed analytical
 hypothesis testing is the primary tool of inference
 Case-control studies
 Simplest and most commonly used analytical strategy in
epidemiology
 Designed primarily to establish the causes of diseases by
investigating associations between exposure to a risk factor
and the occurrence of disease
 Design is relatively simple, except that it is backward-looking
(retrospective) based on the exposure histories of cases and
controls
 one investigates an association by contrasting the exposure of
a series of cases of the specified disease with the exposure
pattern of carefully selected control groups free from that
particular disease
Advantages Disadvantages
Relatively quick and inexpensive great risk of bias in the selection of
cases and
Controls
feasible for rare disease Prone to recall bias (it may be very
difficult or impossible to obtain
information on exposure if the recall
period is long)
Requires a smaller sample size than
cohort study
Cannot measure incidence, only relative
risk is measured
Little problem with attrition, as when
follow-up requires periodic
investigations and some subjects refuse
to continue to cooperate
Cohort studies
 Prospective cohort study
 The common strategy of cohort studies is to start with a reference
population (or a representative sample thereof)
 Some of whom have certain characteristics or attributes relevant to
the study (exposed group), with others who do not have those
characteristics (unexposed group)
 Both groups should, at the outset of the study, be free from the
condition or conditions under consideration
 Both groups are then observed over a specified period to find out the
risk each group has of developing the condition(s) of interest
Design of a cohort (prospective) study
Example of Prospective cohort study design
 Design features
 Selection of cohort
 a community cohort of specific age and sex
 an exposure cohort, e.g. radiologists, smokers, users of oral
contraceptives
 a birth cohort, e.g. school entrants
 an occupational cohort, e.g. miners, military personnel
 a diagnosed or treated cohort, e.g. cases treated with radiotherapy,
surgery, hormonal treatment
The usual procedure is to locate or identify the cohort, which
may be a total population in an area or sample thereof
 Data to be collected
 data on the exposure of interest to the study hypotheses
 data on the outcome of interest to the study hypotheses
 characteristics of the cohort that might confound the association
under study
 Methods of data collection
 Several methods are used to obtain the above data, which should
be on a longitudinal basis.
 These methods include
 Interview surveys with follow-up procedures
 Medical records monitored over time
 Medical examinations and laboratory testing
 Measures of frequency
 Cumulative incidence
 Incidence density (Person-year approach)
 In September 2009, 3000 Birmingham university freshman enrolled in a study
of health behaviors that aimed to track them over 4 years of college. Data from
September 2012 are shown below
 What is the cumulative incidence of obesity over 4 years?
No. of
new
cases
No of
students
“at risk”
at the
begining
Admitted to the emergency room for an alcohol-related
injury
400 3500
Unintended pregnancy? 252 2000
Diagnosed with depression? 310 3000
Obese? 543 2100
 Person-time approach/incidence density
 This approach is an improvement over the conventional
measure of incidence, because it takes into consideration both
the number observed and the duration of observation for each
individual
 If 30 individuals were observed as follows: 10 for two years, 5
for three years, and 15 for four years, they would contribute
(10x2)+(5x3)+(15x4) = 95 person-years of observation, which
would become the denominator. The numerator is the number
of new cases observed in these groups over the specified period
of time………
Advantages Disadvantages
Allow calculation of incidence rates,
relative risk , attributable risk etc.
Expensive
If a probability sample is taken from the
reference population, it is possible to
generalize from the sample to the
reference population with a known
degree of Precision
long-term and sometimes are not
always feasible
capable of identifying other diseases
that may be related to the same risk
factor
Sample sizes required for cohort studies
are extremely large
The most serious problem is that of
attrition
 Historical/retrospective cohort study
 Analytical cross-sectional study
 Investigator measures exposure and disease simultaneously in
a representative sample of the population
 By taking a representative sample, it is possible to generalize
the results obtained in the sample for the population as a
whole
 Cross-sectional studies measure the association between the
exposure variable and existing disease (prevalence)
 Unlike cohort studies, which measure the rate of developing
disease (incidence)
Design of a cross-sectional study
Experimental study designs
 An experiment is the best epidemiological study
design to prove causation
 Viewed as a final or definitive step in the research
process
 A mechanism for confirming or rejecting the validity
of ideas, assumptions, postulates and hypotheses
about the behavior of objects, or effects upon them
which result from interventions under defined sets of
conditions
 Investigator has control of the subjects, the
intervention, outcome measurements, and sets the
conditions under which the experiment is conducted
 In particular, the experimenter determines who will
be exposed to the intervention and who will not
 This selection is done in such a way that the
comparison of outcome measure between the
exposed and unexposed groups is as free of bias as
possible
General experimental study design
 The most commonly encountered experiment in
health science research, and the research strategy by
which evidence of effectiveness is measured, is the
randomized, controlled, double-blind clinical trial,
commonly known as an RCT
 Clinical trials may be done for various purposes
 Some of the common types of clinical trial (according
to purpose) are:
 prophylactic trials, e.g. immunization, contraception
 therapeutic trials, e.g. drug treatment, surgical procedure
 safety trials, e.g. side-effects of oral contraceptives and
injectable
 Risk-factor trials, e.g. withdrawing the agent (e.g. smoking)
through cessation
 Therapeutic trials may be conducted to test efficacy
does a therapeutic agent work in an ideal, controlled
situation?
 or to test effectiveness (e.g. after having established
efficacy, if the therapy is introduced to the
population at large, will it be effective when having
to deal with other co-interventions, confounding,
contamination, etc.?
 The intervention in a clinical trial may include
 drugs for prevention, treatment or palliation
 clinical devices, such as intrauterine devices
 surgical procedures, rehabilitation procedures
 medical counselling
 diet, exercise, change of other lifestyle habits
 risk factors
 communication approaches, e.g. face-to-face communication versus
pamphlets
 different categories of health personnel, e.g. doctors versus nurses
 treatment regimens, e.g. once-a-day dispensation versus three times
a day
 Usually, clinical trials of new therapies or devices
pass through four phases
 Phase I
 Phase II
 Phase III
 Phase IV
Phase I clinical trial
 This first phase in humans is preceded by
considerable research
 Including pharmacological and toxicological studies
in experimental animals
 To establish that the new agent is effective and may
be suitable for human use,
 And to estimate roughly the dose to be used in man
 Phase I trials include studies of volunteers who
receive, initially, a fraction of what the anticipated
dose is likely to be
 And are monitored for effects on body functions,
such as
 Hepatic
 Cardiovascular
 Renal
 Gastroinstestinal
 Endocrinal functions
 The metabolism of the drug may also be investigated
at this stage
 These studies are normally done on volunteers, who
are usually institutionalized, and occupy what are
called ‘research beds’
 Require close supervision
 short duration
Phase II clinical trial
 Also carried out on volunteers selected according to
strict criteria
 Purpose of Phase II is
 to assess the effectiveness of the drug or device
 to determine the appropriate dosage
 to investigate its safety
 Further information on the pharmacology, especially
the dose-response relationship of the drug, is
collected
Phase III clinical trials
 This is the classical phase
 The one usually referred to as a ‘clinical trial’ and
reported in health research journals
 Performed on patients, who should consent to being
in a clinical trial
 Strict criteria for inclusion in and exclusion
 purpose of this phase is
 to assess the effectiveness
 to assess safety in continue use of the drug or device in a larger
and more heterogeneous population than in Phase II
 It includes more detailed studies and monitoring
than those given in a normal service situation
 Usually carried out on hospital inpatients, but may
be performed on outpatients with intense monitoring
follow-up
 It requires superior clinical and epidemiological
skills, in addition to the required laboratory
technology
 Results from these trials are used by regulatory
agencies to evaluate whether a new product or device
should be licensed for general public use
Phase IV
 To identify and evaluate the long-term effects of new
drugs and treatments over a lengthy period for a
greater number of patients.
 Phase IV research takes place after the FDA approves
the marketing of a new drug
 Through Phase IV clinical studies, new drugs can be
tested continuously to uncover more information
about efficacy, safety and side effects after being
approved for marketing
Factors that affect the design of and analysis of
trial (phase III)
 The agent, treatment or experimental factor
 Conditions to be treated
 The target population
 Ethical issues
 Outcomes to be measured
 Side-effects
 Study instruments
 Blinding
 Stopping rule
 Plans for the analysis
 Selective attrition
 Methods for ensuring the integrity of the data
 The choice of design
 Time required
Community intervention trials
 CITs are usually carried out in hospitals or clinics,
and are usually directed at a patient group with
specific health conditions
 a test of whether the introduction of iron-fortified
salt in the community would reduce the incidence of
anemia in the community
 The major difference from the RCT is that the
randomization is done on communities rather than
individuals

Health-Research-Methods-HRM-1.pptx

  • 1.
    M U HA M M A D S A L M A N L E C T U R E R P U N J A B U N I V E R S I T Y C O L L E G E O F P H A R M A C Y Health System Research (HSR)
  • 2.
    Research?  Research simplyseeks the answer of certain questions which have not been answered so far and the answers depend upon human efforts
  • 3.
     Example ofthe moon  Some years ago man did not know what exactly the moon is?  Was this problem which had no solution?  Man could only make some assumptions about it but the man know this time by his efforts, he went to the moon brought the soil of the moon and studied it  The man is now able to give concrete answer of the problem what is the moon?
  • 4.
     Now thequestion arises  “Is the answer of the question in examination also research”?  The answer is ‘no’, because the answers of these questions are available (text-books, class-notes etc)  Research answers only those questions of which the answers are not available in literature i.e., in human knowledge
  • 5.
     Therefore, wecan say research seeks the answer only of those questions of which the answers can be given on the basis of available facilities  Research is simply the process of arriving as dependable solution to a problem through the planned and systematic collection, analysis and interpretation of data  It is the most important process for advancing knowledge for promoting progress  Also enables man to relate more effectively to his environment to accomplish his purpose and to resolve his conflicts
  • 6.
    Term “Research”  Therefore,research means to observe the phenomena again and again from different dimensions
  • 7.
     “Research isa systematized effort to gain new knowledge.” (V. Redman and A.V.H. Mory)  “Research is an honest exhaustive, intelligent searching for facts and their meanings or implications with reference to a given problem. The product or findings of a given piece of research should be an authentic, verifiable and contribution to knowledge in the field studied.” (P.M. Cook)
  • 8.
     He emphasizedthe following characteristics of research in his definition:  It is an honest and exhaustive process.  The facts are studied with understanding.  The facts are discovered in the light of problem. Research is problem-centred.  The findings are valid and verifiable.  Research work should contribute new knowledge in that field
  • 9.
    Objectives of research Theoretical objective  Formulate the new theories, principles or laws.  Such type of research is explanatory because it explains the relationship of certain variables.  These researches contribute some basic knowledge to the human knowledge.  The researches in different disciplines such ads physics, chemistry, mathematics etc. have theoretical objective.
  • 10.
     Factual objective Researches whose objective is factual find out new facts  This objective is by nature descriptive  Application objective  Research having application objective does not contribute a new knowledge in the fund of human knowledge but suggests new applications. By application we mean improvement and modification in practice.  For example if anyone gives a new application of electricity then such type of research has application objective
  • 11.
    General characteristics ofresearch  Gathers new knowledge or data from primary or first –hand sources  Places emphasis upon the discovery of general principles  An exact systematic and accurate investigation  Uses certain valid data gathering devices  Logical and objective  Researcher resists the temptation to seek only the data that support his/her hypotheses  Researcher eliminates personal feelings and preferences  Endeavors to organize data in quantitative terms  Patient and unhurried activity  Researcher is willing to follow his/her procedures to the conclusions that may be unpopular and bring social disapproval  Research is carefully recorded and reported conclusions and generalizations are arrived at carefully and cautiously
  • 12.
     Health research→ A systematic collection, analysis and interpretation of health and health-related data to answer a certain question or to solve a problem  Health systems research also known as health services research or health policy and systems research  Health systems research → "The people, institutions, and activities whose primary purpose is to generate high quality knowledge that can be used to promote, restore, and or maintain the health status of populations. It can include the mechanisms adopted to encourage the utilization of research.“ (HRSA, WHO)
  • 13.
    Classification of Research Basic level  It is designed to add an organized body of scientific knowledge and does not necessarily produce results of immediate practical value  Applied level  Applied research is undertaken to solve an immediate practical problem and the goal of adding to scientific knowledge is secondary
  • 14.
    Kinds of research There are various bases to classify the research  On the basis of objective of the research  Fundamental research  Action research  On the basis of approach of the research  Longitudinal research  Cross sectional research  On the basis of precision in research findings  Experimental research  Non experimental research
  • 15.
     On thebasis of nature of findings  Explanatory research  Descriptive research  According to national science foundation  Basic research: Those researches which embrace origin or unique investigation for the advancement of knowledge  Applied research: which may be characterized as utilization in practice  Developmental research: use of scientific knowledge for the production of useful materials, devices, systems, methods for processes excluding design and production engineering.
  • 16.
    Health research triangle three operational interlinked categories of biomedical, health services and behavioral research, the so-called health research triangle Bio-medical Behavioral Health services
  • 17.
    Research process  Selectionof Research problem  Formulation of hypothesis  Research plan  Data collection  Analysis of data  Formulation of result and conclusions
  • 18.
    Selection and formulationof the problem ?
  • 19.
    Hypothesis  Carefully constructedstatements about a phenomenon in the population  Generated by deductive reasoning, or based on inductive reasoning from prior observations  One of the most useful tools of health research is the generation of hypotheses which, when tested, will lead to the identification of the most likely causes of disease or changes in the condition being observed
  • 20.
     Mill’s canonsof inductive reasoning are frequently utilized in the forming of hypotheses which relate association and causation.  Method of difference - when the frequency of a disease is markedly dissimilar under two circumstances, and a factor can be identified in one circumstance and not the other, this factor, or its absence, may be the cause of the disease  for example → the difference in frequency of lung cancer in smokers and nonsmokers
  • 21.
     Method ofagreement - if a factor, or its absence is common to a number of different circumstances that are found to be associated with the presence of a disease, that factor, or its absence may be causally associated with the disease  The occurrence of hepatitis A is associated with patient contact, poor sanitation and hygiene, each conducive to the transmission of the hepatitis virus
  • 22.
     Method ofconcomitant variation, or the dose response effect  The increasing expression of endemic goiter with decreasing levels of iodine in the diet  The increasing frequency of leukemia with increasing radiation exposure  The increase in prevalence of elephantiasis in areas of increasing filarial endemicity
  • 23.
     Method ofanalogy – the distribution and frequency of a disease or effect may be similar enough to that of some other disease to suggest commonality in cause  e.g. hepatitis B virus infection and cancer of the liver
  • 24.
    Research plan/design  Definingthe population, characteristics of interest and probability distributions  Type of study  observational or experimental
  • 25.
     method ofdata collection, management and analysis:  sample selection  measuring instruments (reliability and validity of instruments)  training of interviewers  quality control of measurements  computerization, checking and validating measurements  the issue of missing observations  statistical summarization of information  testing of hypothesis  ethical considerations  Conclusions
  • 26.
     Deductive Reasoning Thinking precedes from general assumption to specific application GENERAL → SPECIFIC  Inductive reasoning  Conclusions about events are based on information generated through many individual and direct observations SPECIFIC → GENERAL
  • 27.
    Inductive reasoning Deductivereasoning SPECIFIC → GENERAL GENERAL → SPECIFIC Every rabbit has been observed has lungs. Therefore, every rabbit has lungs Every mammal has lungs. All rabbits are mammals. Therefore, every rabbit has lungs.
  • 28.
  • 30.
    Classification  Non-international  AKAobservational studies  Researchers do not manipulate situations/objects  Only describes or analyses situations/objects  Interventional  Participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.
  • 31.
    Non-interventional studies  Descriptivestudies  Case series  Community diagnosis or need assessment  Epidemiological description of disease occurrence  Descriptive cross-sectional studies  Ecological descriptive studies  Analytical studies  Case-control studies  Cohort studies  Prospective cohort studies  Retrospective cohort studies  Analytical cross-sectional studies
  • 32.
    Descriptive studies  Whenan epidemiological study is not structured formally as an analytical or experimental study i.e. when it is not aimed specifically to test a hypothesis, it is called a descriptive study  The wealth of material obtained in most descriptive studies allows the generation of hypotheses, which can then be tested by analytical or experimental designs
  • 33.
     Case series based on reports of a series of cases of a specific condition, or a series of treated cases, with no specifically allocated control group  These represent the numerator of disease occurrence, and should not be used to estimate risks
  • 34.
     Community diagnosisor needs assessment  This kind of study entails collection of data on  existing health problems  Programs  Achievements  Constraints  social stratification  leadership patterns  focal points of resistance or high prevalence, or groups at highest risk.  Its purpose is to identify existing needs and to provide baseline data for the design of further studies or action
  • 35.
     Epidemiological descriptionof the disease occurrence  This common use of the descriptive approach involves the collection of data on the occurrence and distribution of disease in populations according to  specific characteristics of individuals  Age  Sex  Education  Smoking habits  Religion  Occupation  social class  Marital status  Health status  Personality  Place (rural/urban, local, national, international)  Time (epidemic, seasonal, cyclic, secular)
  • 36.
     Descriptive cross-sectionalstudies  AKA population/community surveys  Entail the collection of data on, as the term implies, a cross-section of the population, which may comprise the whole population or a proportion (sample) of it  Many cross-sectional studies do not aim at testing a hypothesis about an association  Provide a prevalence rate at a particular point in time → point prevalence  Or over a period of time → period prevalence
  • 37.
     Ecological descriptivestudies  When the unit of observation is an aggregate (e.g. family, clan or school)  Or an ecological unit (a village, town or country) the study becomes an ecological descriptive study
  • 38.
    Analytical strategies ofepidemiological studies  Observational studies, where establishing a relationship between a ‘risk factor’ (etiological agent) and an outcome (disease) is the primary goal, are termed analytical  hypothesis testing is the primary tool of inference
  • 39.
     Case-control studies Simplest and most commonly used analytical strategy in epidemiology  Designed primarily to establish the causes of diseases by investigating associations between exposure to a risk factor and the occurrence of disease  Design is relatively simple, except that it is backward-looking (retrospective) based on the exposure histories of cases and controls
  • 40.
     one investigatesan association by contrasting the exposure of a series of cases of the specified disease with the exposure pattern of carefully selected control groups free from that particular disease
  • 41.
    Advantages Disadvantages Relatively quickand inexpensive great risk of bias in the selection of cases and Controls feasible for rare disease Prone to recall bias (it may be very difficult or impossible to obtain information on exposure if the recall period is long) Requires a smaller sample size than cohort study Cannot measure incidence, only relative risk is measured Little problem with attrition, as when follow-up requires periodic investigations and some subjects refuse to continue to cooperate
  • 42.
    Cohort studies  Prospectivecohort study  The common strategy of cohort studies is to start with a reference population (or a representative sample thereof)  Some of whom have certain characteristics or attributes relevant to the study (exposed group), with others who do not have those characteristics (unexposed group)  Both groups should, at the outset of the study, be free from the condition or conditions under consideration  Both groups are then observed over a specified period to find out the risk each group has of developing the condition(s) of interest
  • 43.
    Design of acohort (prospective) study
  • 44.
    Example of Prospectivecohort study design
  • 45.
     Design features Selection of cohort  a community cohort of specific age and sex  an exposure cohort, e.g. radiologists, smokers, users of oral contraceptives  a birth cohort, e.g. school entrants  an occupational cohort, e.g. miners, military personnel  a diagnosed or treated cohort, e.g. cases treated with radiotherapy, surgery, hormonal treatment The usual procedure is to locate or identify the cohort, which may be a total population in an area or sample thereof
  • 46.
     Data tobe collected  data on the exposure of interest to the study hypotheses  data on the outcome of interest to the study hypotheses  characteristics of the cohort that might confound the association under study  Methods of data collection  Several methods are used to obtain the above data, which should be on a longitudinal basis.  These methods include  Interview surveys with follow-up procedures  Medical records monitored over time  Medical examinations and laboratory testing
  • 47.
     Measures offrequency  Cumulative incidence  Incidence density (Person-year approach)
  • 48.
     In September2009, 3000 Birmingham university freshman enrolled in a study of health behaviors that aimed to track them over 4 years of college. Data from September 2012 are shown below  What is the cumulative incidence of obesity over 4 years? No. of new cases No of students “at risk” at the begining Admitted to the emergency room for an alcohol-related injury 400 3500 Unintended pregnancy? 252 2000 Diagnosed with depression? 310 3000 Obese? 543 2100
  • 49.
     Person-time approach/incidencedensity  This approach is an improvement over the conventional measure of incidence, because it takes into consideration both the number observed and the duration of observation for each individual  If 30 individuals were observed as follows: 10 for two years, 5 for three years, and 15 for four years, they would contribute (10x2)+(5x3)+(15x4) = 95 person-years of observation, which would become the denominator. The numerator is the number of new cases observed in these groups over the specified period of time………
  • 50.
    Advantages Disadvantages Allow calculationof incidence rates, relative risk , attributable risk etc. Expensive If a probability sample is taken from the reference population, it is possible to generalize from the sample to the reference population with a known degree of Precision long-term and sometimes are not always feasible capable of identifying other diseases that may be related to the same risk factor Sample sizes required for cohort studies are extremely large The most serious problem is that of attrition
  • 51.
  • 52.
     Analytical cross-sectionalstudy  Investigator measures exposure and disease simultaneously in a representative sample of the population  By taking a representative sample, it is possible to generalize the results obtained in the sample for the population as a whole  Cross-sectional studies measure the association between the exposure variable and existing disease (prevalence)  Unlike cohort studies, which measure the rate of developing disease (incidence)
  • 53.
    Design of across-sectional study
  • 54.
    Experimental study designs An experiment is the best epidemiological study design to prove causation  Viewed as a final or definitive step in the research process  A mechanism for confirming or rejecting the validity of ideas, assumptions, postulates and hypotheses about the behavior of objects, or effects upon them which result from interventions under defined sets of conditions
  • 55.
     Investigator hascontrol of the subjects, the intervention, outcome measurements, and sets the conditions under which the experiment is conducted  In particular, the experimenter determines who will be exposed to the intervention and who will not  This selection is done in such a way that the comparison of outcome measure between the exposed and unexposed groups is as free of bias as possible
  • 56.
  • 57.
     The mostcommonly encountered experiment in health science research, and the research strategy by which evidence of effectiveness is measured, is the randomized, controlled, double-blind clinical trial, commonly known as an RCT
  • 59.
     Clinical trialsmay be done for various purposes  Some of the common types of clinical trial (according to purpose) are:  prophylactic trials, e.g. immunization, contraception  therapeutic trials, e.g. drug treatment, surgical procedure  safety trials, e.g. side-effects of oral contraceptives and injectable  Risk-factor trials, e.g. withdrawing the agent (e.g. smoking) through cessation
  • 60.
     Therapeutic trialsmay be conducted to test efficacy does a therapeutic agent work in an ideal, controlled situation?  or to test effectiveness (e.g. after having established efficacy, if the therapy is introduced to the population at large, will it be effective when having to deal with other co-interventions, confounding, contamination, etc.?
  • 61.
     The interventionin a clinical trial may include  drugs for prevention, treatment or palliation  clinical devices, such as intrauterine devices  surgical procedures, rehabilitation procedures  medical counselling  diet, exercise, change of other lifestyle habits  risk factors  communication approaches, e.g. face-to-face communication versus pamphlets  different categories of health personnel, e.g. doctors versus nurses  treatment regimens, e.g. once-a-day dispensation versus three times a day
  • 62.
     Usually, clinicaltrials of new therapies or devices pass through four phases  Phase I  Phase II  Phase III  Phase IV
  • 63.
    Phase I clinicaltrial  This first phase in humans is preceded by considerable research  Including pharmacological and toxicological studies in experimental animals  To establish that the new agent is effective and may be suitable for human use,  And to estimate roughly the dose to be used in man
  • 64.
     Phase Itrials include studies of volunteers who receive, initially, a fraction of what the anticipated dose is likely to be  And are monitored for effects on body functions, such as  Hepatic  Cardiovascular  Renal  Gastroinstestinal  Endocrinal functions
  • 65.
     The metabolismof the drug may also be investigated at this stage  These studies are normally done on volunteers, who are usually institutionalized, and occupy what are called ‘research beds’  Require close supervision  short duration
  • 66.
    Phase II clinicaltrial  Also carried out on volunteers selected according to strict criteria  Purpose of Phase II is  to assess the effectiveness of the drug or device  to determine the appropriate dosage  to investigate its safety  Further information on the pharmacology, especially the dose-response relationship of the drug, is collected
  • 67.
    Phase III clinicaltrials  This is the classical phase  The one usually referred to as a ‘clinical trial’ and reported in health research journals  Performed on patients, who should consent to being in a clinical trial  Strict criteria for inclusion in and exclusion  purpose of this phase is  to assess the effectiveness  to assess safety in continue use of the drug or device in a larger and more heterogeneous population than in Phase II
  • 68.
     It includesmore detailed studies and monitoring than those given in a normal service situation  Usually carried out on hospital inpatients, but may be performed on outpatients with intense monitoring follow-up  It requires superior clinical and epidemiological skills, in addition to the required laboratory technology
  • 69.
     Results fromthese trials are used by regulatory agencies to evaluate whether a new product or device should be licensed for general public use
  • 70.
    Phase IV  Toidentify and evaluate the long-term effects of new drugs and treatments over a lengthy period for a greater number of patients.  Phase IV research takes place after the FDA approves the marketing of a new drug  Through Phase IV clinical studies, new drugs can be tested continuously to uncover more information about efficacy, safety and side effects after being approved for marketing
  • 71.
    Factors that affectthe design of and analysis of trial (phase III)  The agent, treatment or experimental factor  Conditions to be treated  The target population  Ethical issues  Outcomes to be measured  Side-effects  Study instruments  Blinding  Stopping rule  Plans for the analysis  Selective attrition  Methods for ensuring the integrity of the data  The choice of design  Time required
  • 72.
    Community intervention trials CITs are usually carried out in hospitals or clinics, and are usually directed at a patient group with specific health conditions  a test of whether the introduction of iron-fortified salt in the community would reduce the incidence of anemia in the community  The major difference from the RCT is that the randomization is done on communities rather than individuals

Editor's Notes

  • #3 Research has moved during this century from the periphery to the centre of our social and economic life. What is the nature of this force? Why it is getting momentum? Most of us recognize that the progress which has been made in our society has been largely the result of research, we do not have an exact definition of the term. Most of us have a vague idea of what is involved but our concept of research generally is too much oriented toward experimentation as conducted in the social sciences
  • #6 Although it is not the only way, it is one of the more effective ways of solving scientific problems.
  • #8 P.M. Cook has given a very comprehensive and functional definition of the term research
  • #10 Researches whose objectives are theoretical formulate the new theories, principles or laws
  • #14 Trevers has defined basic level as basic research
  • #16 Explanatory research-Such researches explain more concerned theories. laws and principles. DR-more concerned with facts
  • #17 Another way of classify health research, be it empirical or theoretical, basic or applied, is to describe it under three operational interlinked categories Biomedical: deals primarily with basic research involving processes at the cellular level; behavioral: deals with the interaction of man and the environment in a manner reflecting the beliefs, attitudes and practices of the individual in society; health services: Deals with issues in the environment surrounding man, which promote changes at the cellular level
  • #18 Stephen M. Corey
  • #20 Although we cannot draw definite conclusions, or claim proof using the inductive method, we can come ever closer to the truth by knocking down existing hypotheses and replacing them with ones of greater plausibility
  • #21 In health research, hypotheses are often constructed and tested to identify causes of disease and to explain the distribution of disease in populations
  • #23 Elephantiasis refers to a parasitic infection that causes extreme swelling in the arms and legs. The disease is caused by the filarial worm, which is transmitted form human to human via the female mosquito when it takes a blood meal
  • #25 The critical requirement in the design of research, the one that ensures validity, is the evaluation of probability from beginning to end. The most salient elements of design, which are meant to ensure the integrity of probability and the prevention of bias, are: representative sampling, randomization in the selection of study groups, maintenance of comparison groups as controls, blinding of experiments and subjects, and the use of probability (statistical) methods in the analysis and interpretation of outcome. Probability is a measure of the uncertainty or variability of the characteristic among individuals in the population.
  • #31 Many ways but major types are interventional and non-interventional
  • #36 Secular is a descriptive term used to refer to market activities occurring over a long-term time frame.
  • #39 The basic approach in analytical studies is to develop a specific, testable hypothesis, and to design the study to control any extraneous variables that could potentially confound the observed relationship between the studied factor and the disease
  • #48 Cumulative incidence: This incidence measure provides an estimate of the probability or risk of developing disease among all members of the group who were included in the study at its initiation, and were at risk of disease.
  • #50 Person-years do not represent the number of persons: 400 person-years of observation could represent 400 persons each observed for one year, or 40 persons each observed for 10 years
  • #56 In health research, we are often interested in comparative experiment, where one or more groups with specific interventions is compared with a group unexposed to interventions (placebo in clinical trials) or exposed to the best treatment currently available.
  • #66 This phase, which is of short duration (usually one or two months), requires high technology in biochemistry, pharmacology and endocrinology, and varied medical expertise. It also requires access to highly developed laboratory facilities
  • #68 (one could argue that it is still only an efficacy trial, because of the strict conditions under which the study is conducted)
  • #72 Knowledge that is as complete as possible about the treatment should be available to the researchers. This knowledge usually comes from Phase I and Phase II trials, as well as from many ancillary sources. For example, one should know the pharmacological action, toxicity, dose, safety and method of administration of the drug. Stopping rule: Criteria for terminating the trial should be clearly specified. In most cases, a fixed sample size has to be reached before the trial is stopped. A variation on his is the sequential clinical trial, where the results are analysed frequently, and the trial stopped as soon as statistically significant differences are observed.