Download STUDY PROTOCOL

Developing a protocol for a
descriptive epidemiologic study
Talamo
ILARIA CASETTA
FERRARA
Study protocol
• Each study should have a written
protocol
• A protocol is a document that states the
reasoning behind and the design of a
research project
STUDY PROTOCOL: WHY?
To clarify the research question and define
objectives
To plan the project in details before
To check if the objectives can be achieved
To check the feasibility of the study
Prevents failure to collect crucial information
To have a guideline and tool for the research
team
To obtain approval of ethical committee(s)
Application for funds
Makes it much easier to write article
Idea,
Hypothesis
Research
question
Refine
research
question
Planning
Performing
the study
Data analysis
Results,
Interpretation
Dissemination
Knowledge
STUDY PROTOCOL
Principal Components
Protocol
presentation
Background
and rationale
Objectives
Design and
Methods
Data analysis
Ethical issues
References
Budget
Look at
Guidelines for
applicants!
STUDY PROTOCOL
All protocols can be divided into two main sections:
(i) the problem to be investigated and (ii) the method
of investigation.
Problem to be investigated
1. Background (literature review)/rationale
2. Objectives
BACKGROUND and RATIONALE
Review the relevant literature
• What is already known? Is there consensus? Is
there controversy? Is there conclusive
evidence? What remains to be answered?
• Why is the research important?
• What kind of answer will the study provide?
• What is the ultimate purpose that the
knowledge obtained from the study will serve?
OBJECTIVES
MMain objective
• Must be achieved
• Dictates design and
methods
Secondary objectives
• Of interest, but not
essential
• Logical and coherent
• Feasible
• Realistic, considering
local conditions
• Defined in operational
terms that can be
measured
• Relevant
Use action verbes : i.e.
“To estimate…, To
compare..., To verify...,
To describe..., etc.
FINER - Criteria for a Good Research Question
(Hulley)
• Feasible
Affordable in time and money
Manageable in scope. Appropriate skills and
expertise of the group
• Interesting
• 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
STUDY PROTOCOL- Methods
All protocols can be divided into two main sections:
(i) the problem to be investigated and (ii) the
method of investigation.
1. Study design
2. Study population
3. Diagnostic criteria
4. Case definition
5. Case collection and ascertainment
6. Data Collection
STUDY DESIGN and METHODS
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 1997;315:1636
Timeframe of Studies
Cross-sectional
Prospective
time
Retrospective
time
STUDY PROTOCOL- Methods
1. Study design
2. Study population
3. Diagnostic criteria
4. Case definition
5. Case collection and ascertainment
6. Data Collection
 Defining the
population at risk of
disease
 Denominator
 Classifying and
categorizing disease
 Diagnostic criteria
 Deciding what
constitutes a case of
disease in a study
 Inclusion and
exclusion criteria
Case definition
METHODS
METHODS
Population at risk
• Geographical
bundaries (study
area-setting)
• Specific populations
– Demographic
– Others
(occupational,
exposures,…)
• Population sample
(sampling
procedure)
Appropriate for study
objectives
Defining the population at risk of
disease ( denominator)
• Study area
Define the size,
characteristics, health
organization
• Population
Total, by sex and age
groups (Census data)
• Temporal
boundaries
• Incidence interval
• Prevalence point (period)
Epilepsy in Sardinia, Insular Italy: A PopulationBased Prevalence Study
• The study area will be the province of Sassari, north-western
Sardinia, with a surface of 4,282 Km2. It comprises 66
municipalities…The province population is 333,576 (163,104 men
and 170,472 women), December 31, 2007.
• The Section of Neurology, University of Sassari, hosts the referral
Centre for Epilepsy of northern Sardinia. Other relevant structures
for medical care of adult epileptic patients in the study area are the
Division of Neurology, sub-Health District Hospital of Ozieri, the
Departments of Internal Medicine in sub-Health Districts of Sassari,
Alghero and Ozieri. Few consultant neurologists practising for the
National Health System (NHS) territorial services in the study area
……provide care to epileptic patients.
• Since year 2000, Sassari Health District has benefited from the
Health Information System Unit (HISU) where health information is
collected at population-based level into electronic datasets, including
hospital discharge records and disease specific medical care fare
exemptions.
Case definition- problems
• Diagnostic criteria may vary over time
• Different level of diagnostic certainty
• Definite diagnosis may require postmortem examination
• Onset of the disease?
• Lag time between onset and diagnosis
deciding what constitutes a
case of disease
• Diagnostic
Criteria
• Inclusion
and
exclusion
criteria
The diagnosis of ALS will based on the first version
of the El Escorial criteria. These criteria distinguish
four levels of diagnostic certainty: definite,
probable, possible, and suspected ALS. All the
diagnostic levels will be considered for the
calculation of incidence. Cases with progressive
bulbar palsy (PBP), progressive muscular atrophy
(PMA), and primary lateral sclerosis (PLS) well be
included.
Individuals under the age of 18 will be excluded to
avoid misclassification of other motor neuron
diseases of genetic origin, mimicking ALS.
We will use MG to reclassify cases according to the
revised El-Escorial criteria.
Modified from Logroscino et al, 2005
STUDY PROTOCOL- Methods
1. Study design
2. Study population
3. Diagnostic criteria
4. Case definition
5. Case collection and ascertainment
6. Data Collection
CASE COLLECTION and
ASCERTAINMENT
• Existing diagnoses (Hospital, Services,
Drug prescription, Notification system,
Registers, Discharge diagnoses, family
doctors……)
• Direct contact survey
Multiple sources of
data
Prevalence study
Hospital records,
Outpatient services
EEG services
Laboratory for AEDs
assays
Discharge diagnoses
Exemption codes
CASE and DATA COLLECTION
• How?
• By whom?
• Tools? Describe instruments used!
Recording materials (Case Record Forms),
Questionnaires , ..)
Data handling and
processing
• Data coding
• Data entry, data quality
control
• Data analysis
Incidence (mortality)
rate, Prevalence, 95%
CIs, Variable-specific
rates, Adjusted rate
Ethical issues
• Confidentiality, anonymity
• Informed consent
• Data storage and
protection
Other aspects
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Participating Collegues/Centers
Tasks of each participant/Center
Timetable, work plan, project milestones
Data Ownership
Publication policy
Resources-Budget
References
Additional material ( data collection
instruments, questionnaires, consent form..)
COMMON PROBLEMS
• Insufficient attention to literature
• Failure to provide the proper context to frame the
research question.
• Failure to cite relevant studies
• Poor justification, failure to develop a persuasive
argument for the proposed research.
• Poor description/poor methodology
• Proposing more work than can be reasonably done
during the grant/study period
• Too much detail on minor issues, but not enough
detail on major issues.
• Too long / verbose or too short.