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Study protocol

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Title: Study protocol


1
Study protocol
  • Jim teWaterNaude
  • UCT Dept Public Health

2
Research
  • The process of asking and answering a question

3
Protocol
  • The reason for having for a study plan or
    protocol is efficiency
  • You want to be able to do the intended study
    quickly, cheaply, easily and ethically, and with
    no major oh-my-gosh-I-didnt-think-of-that
    moments.
  • Here follow 3 examples of protocol outlines

4
1. Study protocol outline(This is the preferred
style, as found in Hulley)
Element Purpose
1. Research questions What questions will the study address?
2. Significance (background) Why are these questions important?
3. Design Time frame Epidemiologic approach How is the study structured?
4. Subjects Selection criteria Sampling design Who are the subjects and how will they be selected?
5. Variables Predictor variables Confounding variables Outcome variables What measurements will be made?
6. Statistical issues Hypotheses Sample size Analytic approach How large is the study and how will it be analyzed?
5
Hulley explains the process in familiar terms
  • Anatomy of research(what its made of)
  • Research question
  • Significance
  • Design
  • Subjects
  • Population
  • Sample size
  • Variables
  • Predictor
  • Outcome
  • Physiology of research (how it works)
  • Using measurements in a sample to draw inferences
    about phenomena in a population

6
2. Major headings in a protocol(MRC approach)
  • Title
  • Investigators, institutional affiliations,
    qualifications
  • Summary/Abstract
  • 1. Introduction
  • Literature review Motivation for the study
    (problem) Purpose Specific objectives
    Implementation objectives
  • 2. Methods
  • Definition of terms Study design Study
    population and sampling Measurements Pilot
    studies
  • 3. Logistics and time schedule
  • Responsibilities of investigators and of staff
    Time schedule
  • 4. Data management and analysis
  • 5. Resources
  • Available resources Budget and budget motivation
  • 6. Ethical and legal considerations
  • 7. Reporting of results
  • 8. Appendices

7
3. Components of a research proposal(Shi)
  • Title page
  • Table of contents
  • Abstract
  • Project Description
  • Introduction
  • Problem statement and significance
  • Goals and objectives
  • Methods and procedures
  • Evaluation
  • Dissemination
  • References
  • Budget and Justification
  • Human Subjects
  • Appendices

8
Main protocol elements
  • The above protocol outlines have these as main
    elements
  • Population
  • Question
  • Relevance
  • Study design and variables
  • Timeframe
  • To understand these, we need to revisit some
    epidemiology

9
Epidemiology
  • The study of the distribution and determinants of
    health in humans
  • It is the science of the occurrence of disease in
    human populations

10
distribution and determinants
  • Distribution
  • What (the disease), plus when where
    who
  • or the disease described by TIME PLACE
    POPULATION
  • Determinants
  • The Why
  • the causes, or risk factors

11
distribution and determinants
  • Distribution
  • What, when, where, who
  • Descriptive studies
  • Determinants
  • Why
  • What is associated with/ caused by
  • Analytic studies
  • Interventive studies

12
Population
  • a group sharing certain common characteristics
  • Do not have to be people (most often are)
  • Can be records, institutions, farms, events
  • Does need to be clearly defined and specified

13
Question
  • Questions arise out of involvement in the field
  • The research question occurs in 3 layers
  • The conceptual research question is what the
    investigator wants to know about the world
  • The operational research question is what is
    deemed achievable though the deliberations of
    drawing up the study plan or protocol
  • The actual research question is what actually
    gets answered during the conduct of the study.

14
The research cycle(after Hulley)
15
The research cycle
Target population Phenomena of interest
Intended sample Intended variables
Actual subjects Actual measurements
16
Research the process of asking and answering a
question
Asking your question
Answering your question
17
Asking your question Background Methods
Results
Discussion Answering your question
18
Asking your question General Specific
Specific
General Answering your question
19
Asking your question Conceptual Operational
Ope
rational Conceptual Answering your question
20
  • Asking your question
  • Background
  • Literature review
  • Objectives
  • Methods
  • Design
  • Measurements

21
  • Results
  • Limitations
  • Findings
  • Discussion
  • What this means
  • Conclusion
  • Answering your question

22
Research questions using existing data
  • Choose a database
  • Become thoroughly familiar with all variables and
    how they were measured
  • Identify variables whose association may be of
    interest
  • Review the literature and consult experts to
    determine relevant research questions
  • Formulate specific hypotheses and settle on the
    statistical methods
  • Table 13.1 in Designing Clinical Research
  • Will you use existing, or generate your own data?

23
but it doesnt mean anything(one of the
childrens lament from Sound of Music)
  • Population
  • Question
  • Relevance (it has to mean something)
  • Study design and variables
  • Timeframe

24
Relevance
  • FINER - Criteria for a Good Research Question
  • Table 2.1 in Hulley
  • Feasible
  • Adequate number of subjects
  • Adequate technical expertise
  • Affordable in time and money
  • Manageable in scope
  • Interesting
  • To the investigator
  • Novel
  • Confirms or refutes previous findings
  • Extends previous findings
  • Provides new findings
  • Ethical
  • Relevant
  • To scientific knowledge
  • To clinical and health policy
  • To future research directions

25
Study design and variables
  • There are 2 broad study design classes and
  • 2 broad variable classes.
  • Which is the best study design?
  • The question being asked determines the
    appropriate research architecture, strategy, and
    tactics to be used
  • This is quoted from the accompanying editorial
  • Sackett DL, Wennberg JE. Choosing the best
    research design for each question. Editorial. BMJ
    19973151636

26
Study designs- arranged in ascending order of
credibility
  • Case reports
  • Case series
  • Correlational studies
  • Cross-sectional studies
  • Case-control studies
  • Cohort studies
  • Controlled trials

27
2 broad study design classes
  • Descriptive and analytic
  • In descriptive epidemiology, we describe the
    distribution of an exposure or outcome, without
    overtly seeking to explain the distribution by
    looking for associations
  • (distribution of health in humans)
  • In analytical epidemiology, we examine
    associations, often with the aim of identifying
    possible causes for an outcome
  • (determinants of health in humans)

28
Analytic study designs
  • Observational and interventional
  • In observational epidemiology we examine the
    distribution or determinants of an outcome
    without any attempt to influence them
  • (examples are smoking, drinking, sexual
    behaviours)
  • In interventional epidemiology we test a
    hypothesis by modifying an exposure within the
    study population and examining the effect on the
    outcome
  • (examples are vaccine or drug trials)

29
2 broad variable classes
  • Exposure and outcome variables
  • Exposures are also called risk factors, factors,
    predictor variables, independent variables.
  • These may or may not be the cause of the outcome
    we determine this through research
  • Outcomes are also called effects, dependent
    variables, diseases, events, or health-related
    states that we are interested in

30
Time frame
  • Rule of halves
  • Spend half on Asking
  • ½ on Background
  • ½ on Methods
  • Spend half on Answering
  • ½ on Results
  • ½ on Discussion
  • ½ ½ ½ ½ 1

31
Epidemiological terms not covered
  • Quantitative and Qualitative
  • Validity and Variability
  • Causality/ Causal inference
  • Bias
  • Confounding
  • The 2x2 table
  • Occurrence and effect measures

32
Protocol more comments
  • The scientific thinking that goes into the
    protocol attempts to control the errors that
    commonly occur these errors are either random
    (due to chance) or systematic (due to bias)
  • Developing a protocol is an iterative process of
    drafting and redrafting, visiting and revisiting,
    and is best approached initially by divergent
    rather than convergent thinking
  • The perfect study has yet to be done, as there
    are many trade-offs in the process of asking and
    answering your question

33
An example of applying PQRST- the Dop system
  • Population
  • Productive farms in the Stellenbosch district
  • Question
  • What is the current prevalence of the Dop system
    (in 1995)?
  • Relevance
  • Never previously documented. Presumed health
    effects
  • Study design and variables
  • Cross-sectional descriptive. Frequency amount
    of dop
  • Timeframe
  • 4 months in all. 3-4 weeks for data collection,
    collected by nurses on their mobile clinic visits
    to the farms

34
Apply PQRST
35
1st Task at the lecture- task taken from Chapter
1 of the textbook
  • For each of the following 4 abstracts
  • State the research question in a single sentence
    that specifies the predictor and the outcome
    variables, as well as the population sampled
  • State the study design. Think also about the main
    inference that can be drawn from the study, to
    whom it can be generalised, and what the
    potential errors in drawing and applying these
    inferences are
  • (Answers are given at the very end of this
    presentation)

36
  • a. Giving vitamin D to patients with vitamin D
    deficiency can improve strength. To find out
    whether the ordinary weakness of aging could be
    treated with vitamin D, we selected 38 men and
    women 70 years of age and greater from a
    hypertension treatment clinic and randomly
    assigned them to receive either vitamin D3 or
    identical placebo. Muscle strength of the
    quadriceps, measured with an isokinetic
    dynamometer after 6 months of treatment, was
    similar in the two groups.
  • The research question
  • The study design

37
  • b. To assess whether the sedative effects of
    psychotropic drugs might cause hip fractures, we
    studied 1021 men and women with hip fractures and
    5606 without hip fractures among elderly Medicaid
    enrollees. Persons treated with short-acting
    tranquillizers had no increased risk of hip
    fracture. By contrast, there was an increased
    risk associated with current use of
    tranquillizers having half-lives of more than 24
    hours (odds ratio, 1.8 95 percent confidence
    interval, 1.3 to 2.4).
  • The research question
  • The study design

38
  • c. Knowledge about AIDS was studied among 893
    teenaged boys and 633 girls drawn from 12
    secondary schools in Zimbabwe. Ninety-three
    percent of the children thought that it was an
    infection caused by having sexual relations, and
    10 believed that it could be contracted from
    toilet seats.
  • The research question
  • The study design

39
  • d. We examined the use of estrogen replacement
    therapy in relation to breast cancer in
    postmenopausal women. During 367 187 person-years
    of follow-up, there were 722 new cases of breast
    cancer. The risk of breast cancer was
    significantly elevated among current estrogen
    users (relative risk, 1.36 95 confidence
    interval, 1.11 to 1.67), but not among former
    users.
  • The research question
  • The study design

40
2nd Task at the lecture
  • Write down your own Research Question in one
    sentence

41
Task for September
  • Get the book
  • Get a research mentor in your department
  • Decide on your area of research. Will you use
    existing or generate new data?
  • Compose your one sentence Research Question
  • Flesh this out into a half-page study plan or
    protocol, using a structure that suits you. Start
    your literate review.
  • Submit this to jim_at_cormack.uct.ac.za for feedback

42
Task for December
  • Complete your 5-page protocol(format outline in
    the next slide)
  • Submit this to jim_at_cormack.uct.ac.za for feedback

43
5-page protocol
  • Title
  • Abstract
  • Specific aims
  • Significance (limit to 1/2 page)
  • Design
  • Overview (time frame and nature of control)
  • Study subjects (selection criteria, plans for
    recruiting)
  • Measurements (predictors, confounders, outcomes)
  • Statistical issues (hypotheses and sample size)
  • Pretests, quality control, data management
  • Timetable
  • Addendum Ethical considerations (not part of the
    5 pages)

44

Its not how you start, its how you finish 9
times winner Bruce Fordyce, describing the
Comrades Marathon
  • (but do please get to the start line)
  • Many thanks
  • UCT Dept Public Health

45
  • a. Giving vitamin D to patients with vitamin D
    deficiency can improve strength. To find out
    whether the ordinary weakness of aging could be
    treated with vitamin D, we selected 38 men and
    women 70 years of age and greater from a
    hypertension treatment clinic and randomly
    assigned them to receive either vitamin D3 or
    identical placebo. Muscle strength of the
    quadriceps, measured with an isokinetic
    dynamometer after 6 months of treatment, was
    similar in the two groups.
  • 1. Does treatment with vitamin D increase leg
    muscle strength in healthy people 70 years of age
    or greater?
  • Audience comment Healthy should read
    Hypertensive
  • 2. Randomised blinded trial

46
  • b. To assess whether the sedative effects of
    psychotropic drugs might cause hip fractures, we
    studied 1021 men and women with hip fractures and
    5606 without hip fractures among elderly Medicaid
    enrollees. Persons treated with short-acting
    tranquillizers had no increased risk of hip
    fracture. By contrast, there was an increased
    risk associated with current use of
    tranquillizers having half-lives of more than 24
    hours (odds ratio, 1.8 95 percent confidence
    interval, 1.3 to 2.4).
  • 1. Do psychotropic medications increase risk for
    hip fracture among elderly men and women?
  • 2. Case-control study
  • Audience comment Surely this could be a
    cross-sectional study?
  • Response Yes, but the wording seems to favour
    case-control, because they mention the hip
    fracture group as if they had been initially
    selected before the controls were selected,
    reflecting the conduct of a case-control study.
    Another clue is the use of odds ratio, which is
    synonymous with case-control studies

47
  • c. Knowledge about AIDS was studied among 893
    teenaged boys and 633 girls drawn from 12
    secondary schools in Zimbabwe. Ninety-three
    percent of the children thought that it was an
    infection caused by having sexual relations, and
    10 believed that it could be contracted from
    toilet seats.
  • 1. What is the state of knowledge about AIDS
    among schoolchildren in Zimbabwe?
  • 2. Cross sectional descriptive study

48
  • d. We examined the use of estrogen replacement
    therapy in relation to breast cancer in
    postmenopausal women. During 367 187 person-years
    of follow-up, there were 722 new cases of breast
    cancer. The risk of breast cancer was
    significantly elevated among current estrogen
    users (relative risk, 1.36 95 confidence
    interval, 1.11 to 1.67), but not among former
    users.
  • 1. Does estrogen replacement therapy in
    postmenopausal women increase risk for breast
    cancer?
  • 2. Cohort study
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