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Developing a protocol for a descriptive epidemiologic study

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?.

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Developing a protocol for a descriptive epidemiologic study

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  1. Developing a protocol for a descriptive epidemiologic study Talamo ILARIA CASETTA FERRARA

  2. 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

  3. 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

  4. Knowledge Idea, Hypothesis Research question Refine research question Planning Performing the study Data analysis Results, Interpretation Dissemination

  5. STUDY PROTOCOL PrincipalComponents • Protocol presentation • Background and rationale • Objectives • Design and Methods • Data analysis • Ethical issues • References • Budget Look at Guidelines for applicants!

  6. STUDY PROTOCOL Allprotocols can bedividedintotwomainsections: (i) the problemtobeinvestigatedand (ii) the methodofinvestigation. Problemtobeinvestigated • Background (literaturereview)/rationale • Objectives

  7. BACKGROUND and RATIONALE • 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? Review the relevantliterature

  8. 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.

  9. 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

  10. STUDY PROTOCOL- Methods Allprotocols can bedividedintotwomainsections: (i) the problemtobeinvestigated and (ii) the methodofinvestigation. Study design Studypopulation Diagnosticcriteria Case definition Case collection and ascertainment Data Collection

  11. 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

  12. time Timeframe of Studies Cross-sectional Prospective Retrospective time

  13. STUDY PROTOCOL- Methods Study design Studypopulation Diagnosticcriteria Case definition Case collection and ascertainment Data Collection

  14. METHODS • Defining the population at risk of disease • Classifying and categorizing disease • Deciding what constitutes a case of disease in a study • Denominator • Diagnostic criteria • Inclusion and exclusion criteria Case definition

  15. METHODS Population at risk • Geographical bundaries (study area-setting) • Specific populations • Demographic • Others (occupational, exposures,…) • Population sample (sampling procedure) • Appropriate for study objectives

  16. Defining the population at risk of disease ( denominator) Define the size, characteristics, health organization Total, by sex and age groups (Census data) • Incidence interval • Prevalence point (period) • Study area • Population • Temporal boundaries

  17. Epilepsy in Sardinia, Insular Italy: A Population-Based 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.

  18. Case definition- problems • Diagnostic criteria may vary over time • Different level of diagnostic certainty • Definite diagnosis may require post-mortem examination • Onset of the disease? • Lag time between onset and diagnosis

  19. 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

  20. STUDY PROTOCOL- Methods Study design Studypopulation Diagnosticcriteria Case definition Case collection and ascertainment Data Collection

  21. CASE COLLECTION and ASCERTAINMENT • Existing diagnoses (Hospital, Services, Drug prescription, Notification system, Registers, Discharge diagnoses, family doctors……) • Direct contact survey

  22. Multiple sources of data • Prevalence study • Hospital records, • Outpatient services • EEG services • Laboratory for AEDs assays • Discharge diagnoses • Exemption codes

  23. CASE and DATA COLLECTION • How? • By whom? • Tools? Describe instruments used! Recording materials (Case Record Forms), Questionnaires , ..)

  24. Data handling and processing Confidentiality, anonymity Informed consent Data storage and protection Ethical issues • Data coding • Data entry, data quality control • Data analysis Incidence (mortality) rate, Prevalence, 95% CIs, Variable-specific rates, Adjusted rate

  25. Otheraspects • 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..)

  26. 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.

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