The document discusses various study designs used in clinical research, including descriptive studies, analytical studies, randomized controlled trials, and cohort studies. It provides an overview of the characteristics, strengths, and weaknesses of different study designs. For example, it notes that case-control studies can examine many exposures but cannot measure incidence, while cohort studies provide incidence data but are time-consuming and expensive. The document emphasizes choosing an appropriate study design based on the research question.
2. How to conduct a clinical
trial
Research question
Study designs
CONSORT step-by-step
Sample size and power calculations
Randomization and blinding
Data processing
Simple-minded guide to hypothesis
testing
3.
4. Research Process
Research question
Background of the research
Study design
Study population
Study variables
Data Collection
Quality control
Statistical analysis
Dissemination of data
5. Good research depends on
a clear question
understanding the context of the
question
being able to use appropriate methods
to answer the question
knowing when to stop
6. Starting points
Discussion with a supervisor or colleagues,
email, discussion groups, mailing lists
Databases - Cochrane, NEXUS, Project
Impact.
"further research needed" sections of
journal articles, papers, theses and
dissertations in the subject area of your
interest
Topic definitions in encyclopaedias and
"state-of-the-discipline" reviews in the
journal literature
7. What are you looking for?
topics where there is doubt and uncertainty
disputed or contradicted statements
topics where evidence is incomplete,
lacking, dated
topics where evidence from a study on one
community or group could be compared
with evidence from an associated group
topics which interest you
8. Requirements
Mastering the literature
Being alert to new ideas and techniques
Conferences
Meet researchers
Skeptical attitude
New technologies
Imagination
Observation
Teaching
Creativity
Tenacity
Choosing a mentor
9. Good research question
Feasible
No. of Subjects
Technical expertise
Affordable in time and money
Manageable in scope
Interesting
Novel
Confirms, refutes or extends previous findings
New findings
Ethical
Relevant
Scientific knowledge
Clinical and health policy
Future research
14. Cross-sectional studies
Characteristics
Data collected at single point of time
Describes associations
Prevalence
Strengths
Quick
Cheap
Weaknesses
Can’t establish cause-effect
15. Case-Control Study
Start with people who have disease
Match them with controls that do not
Look back and assess exposures
16. Case-Control Study:
Strengths
Good for rare outcmes
Can examine many exposures
Useful to generate hypotheses
Fast
Cheap
Provides Odds Ratio
18. Cohort Study
Begin with disease-free patients
Classify patients as exposed/unexposed
Record outcomes in both groups
Compare outcomes using relative risk
19. Cohort Study: Strengths
Provides incidence data
Establishes time sequence for causality
Eliminates recall bias
Allows for accurate measurement of exposure
variables
Can measure multiple outcomes
Can adjust for confounding variables
Can calculate relative risk
20. Cohort Study: Weaknesses
Expensive
Time consuming
Cannot study rare outcomes
Confounding variables
Exposure may change over time
Disease may have a long pre-clinical phase
Attrition of study population
22. Randomized Controlled
Trial
Outcome
Treatment
Group
Randomization
No Outcome
Study
Population
Outcome
Control
Group
No Outcome
23. Clinical Trials
Strengths:
Best measure of causal relationship
Best design for controlling bias
Can measure multiple outcomes
Weaknesses:
High cost
Ethical issues may be a problem
Compliance
24.
25. Clinical decisions
Patient’s circumstances
Evidence
and wishes
Clinical Audit Technology assessment
Strategies
to Practice Economic Systematic Primary
implement guidelines studies reviews studies
guidelines