CHP400: Community Health Program - lI Mohamed M. B. Alnoor Research Methodology STUDY DESIGNS Observational / Analytical Studies Present: Disease Past:

CHP400:Community Health Program - lI

Mohamed M. B. Alnoor

Research Methodology

STUDY DESIGNSObservational / Analytical Studies

Present: Disease Past: Exposure

Cross - section Cohort

Case - control

Present:Disease & Exposure

Present: Exposure Future: Disease

nbmmb

Time is Key

Clinical trial

STUDY DESIGNS


Clinical trials

Experimental studies

Definition &rationale Types of Trials Phases of Clinical Trials Steps of clinical trial

• Develop the study concept• Prepare a protocol for the study• Protect participants• Conduct and Monitor the study• Analyze study data and interpret the results• Communicate the results

Content

STUDY DESIGNS

ExperimentalObservational

Animal

Experiment

HumanInterventio

nClinical trial

Analytical

Case control

Descriptive

Case report

Case series

Cross section

Ecological

Cohort


Clinical trial

History

Perhaps the first ever clinical trial was James Lind’s demonstration in 1753 that citrus fruits cured scurvy. He compared the effects of various different acidic substances ranging from vinegar to cider, on groups of sailors, and found that the group who were given oranges and lemons had largely recovered from scurvy after 6 days.

STUDY DESIGNS


Experimental studiesClinical trials

Definition:

A planned experiment on humans. The setting is usually a health institutions and it usually involves patients.Rationale:Before a new treatment method is made available to the public it must be studied and tested for safety and effectiveness.

STUDY DESIGNS


Clinical trials


STUDY DESIGNS


Clinical trials


Treatment Prevention Diagnostic Screening Quality of Life

Types of Trials

STUDY DESIGNS


Clinical trials

Treatment Trials

New treatments for that disease?

Most effective treatment for that disease?


STUDY DESIGNS


Clinical trials

Phases of Clinical Trials

Most trials that involve new drugs go through a series of steps:#1: Experiments in the laboratory#2: Once deemed safe, go through 1-

4 phases


STUDY DESIGNS


Clinical trials


NN

20 –100

Up to several 100s

Phase IIPhase II

100s – several 1000s

Phase IIIPhase III

Phase IPhase I

LengthLength

Several monthsSeveral months- 2 yrs.

1-4 yrs.Safety, dosage & effectiveness

Short term safety; mainly effectiveness

Mainly Safety

PurposePurpose% Drugs% Drugs

Successfully Successfully TestedTested

70%

33%

25-30%

Phases of Clinical Trials

STUDY DESIGNS


Clinical trials


Protect participants

Communicate the results

Steps of clinical trial Prepare a protocol for the study

Develop the study concept

Analyze study data and interpret the results

Conduct and Monitor the study

STUDY DESIGNS


Clinical trials


Develop the study concept

• Review current research

• Formulate hypothesis

• Providing the evidence

• Review of the concept and feedback.

Steps of clinical trial

STUDY DESIGNS


Clinical trials


• Purpose , value and methods

• Eligibility and exclusion criteria

• Details of the therapy

• Data to be gathered

• Study endpoints

Prepare a protocol for the studySteps of clinical trial

STUDY DESIGNS


Clinical trials


Sample

Intervention

Control

OUTCOME


Follow upReferencePopulation

• Defining the study design

STUDY DESIGNS


Clinical trials


Prepare a protocol for the study

• Randomized Controlled Trial

• Difficulties with blinding


• Single -Blind vs Double-Blind Studies

STUDY DESIGNS


Clinical trials


Clinical trials

Investigational Group


Ra

nd

om

izatio

nRandom

ization

Random

ization

Random

ization

Random

ization

Random

ization

Random

ization

Ra

nd

om

izatio

n

Random

ization

Random

ization

• Randomization

STUDY DESIGNS


Clinical trials


Protect participants

• Informed consent

• Institutional Review Board

Procedures and treatments/duration Tests Possible risks and benefits


• Good Clinical Practice guidelines

• Benefits/Risks of participation in Clinical Trials

STUDY DESIGNS


Clinical trials


Conduct and Monitor the study• Follows the study protocol

• Detailed schedule for participant (what each visit involves)

• Ongoing monitoring to report adverse events


• Study team

STUDY DESIGNS


Clinical trials


Analyze study data and interpret the results

• Type of analysis is dictated by goals and objectives

• Minimize bias and uncertainty


incomplete data terminology attrition specified analyses statistical analytic plan

• Analysis follows study protocol

STUDY DESIGNS


Clinical trials


Analyze study data and interpret the resultsSteps of clinical trial

Relative Risk(RR):

--------------------------------RR=

Groupoutcome

TotalPositive Negative

Intervention a b a+b

Control c d c+d

TotalExperimental Event Rate (EER)

Control Event Rate (CER )

STUDY DESIGNS


Clinical trials



Relative Risk(RR):

Groupoutcome

TotalDeath Survival

Ligation 18 46 64Sclerotherapy 32 33 65

Total

--------------------------------RR=Experimental Event Rate (EER)


STUDY DESIGNS


Clinical trials



Relative Risk(RR):

----------

RR=Experimental Event Rate (EER)


Statistical power

EER = a/(a+b)

18/64

CER = c/(c+d)

32/65RR= = 0.57

--------------------------------

GroupOutcome

TotalDea

thSurvival

Ligation 18 46 64Scleroth-

erapy32 33 65

=18/64

=32/65

STUDY DESIGNS


Clinical trials


Communicate the results Steps of clinical trial

• with participants • with the medical community • with other researchers • with the general public

Sharing information

STUDY DESIGNS


Clinical trials


Communicate the results Steps of clinical trial

• publishing a report• community newsletter• issuing a news release• holding a news conference• presenting at a meeting or conference• publishing an abstract• creating a brochure.

Communicating study findings

STUDY DESIGNS


Clinical trials

Follow-up

RQ: Does diet and exercise reduce risk of developing type 2 diabetes in persons with glucose intolerance?

Design: Randomized trialSubjects: 2500 with glucose intoleranceIntervention: low fat diet and moderate intensity

aerobic exerciseoutcome = development of frank diabetes


STUDY DESIGNS


Clinical trials

Diet and Exercise to Prevent Diabetes in Persons with Glucose Intolerance

DM No DM

D&E

No D& E

6565 560560

125125 500500

625625

625625

10601060190190 12501250

RR = 0.52; p = .001RR = 0.52; p = .001


Case reports

Case series

Case-control studies

Randomized controlled studies

Ecological studies

Cross-sectional studies

Cohort studies

Generate hypotheses

Establish causality


STUDY DESIGNS


Clinical trials

STUDY DESIGNS


Clinical trials

Conclusions & Take Home Message

Clinical trials often yield important results that affect health and well being

Must follow guidelines & protocol Must ensure well-being of participant Clinical trials are susceptible to human error

either on part of investigator or patient Rank high in the ladder of causality


Documents

CHP400: Community Health Program - lI Mohamed M. B. Alnoor Research Methodology STUDY DESIGNS Observational / Analytical Studies Present: Disease Past: