cochrane workshop picos

Defining a Researchable

Question: the PICOS Approach

Cochrane Reviewers’ Training Workshop

January 22-23, 2009

Session Presenter: Marcus Vaska

Slides adapted from “Defining a Researchable Question..” by

Miranda Cumpston, with additions and deletions by Dr. Roger

Thomas; “Review Protocol and Designing Your Research Question,”

by the Cochrane Collaboration

Session Goals

Learn about strategies/tips used to help

design a research question

Learn about the PICOS approach, and be

able to apply this method when defining your

own researchable question

Strategies/Tips for Designing a

Research Question

Main Objective: summarize the question in order to help the reader understand the evidence and/or make a practical decision about a health care decision

Remember: Remain neutral, not biased (do not impose own values and/or

preferences when defining your research question)

Although you may be an expert in your particular subject area, don’t assume your readership is. Therefore, the Cochrane review needs to be easy to understand and follow by a person who may have only marginal knowledge about the topic.

A Brief Note on

Cochrane Review Titles

All Cochrane titles and reviews of diagnostic tests utilize one of the following standard formats: <intervention> for <health problem>

i.e. <antibiotics> for <tuberculosis>

<intervention A> vs. <intervention B. for <health problem> i.e. <modern medicine> vs. <traditional, homeopathic

remedies> for <malaria>

<intervention> for <health problem> in <participant group/location> i.e. <education programs> for <AIDS> in

<pastoralist/nomadic societies>

Sample Topic for

Demonstration Purposes

In lieu of traditional homeopathic remedies,

can the administration of modern

medicine help alleviate the malaria

epidemic among children in Africa?

The PICOS Approach:

What is it and Why is it Important?

PICOS = a framework designed to make the process of defining and designing a research question easier

Why is it Important? To create a clear question

To identify the information needed to answer that question

To translate the question into searchable terms

To develop and refine the search approach

“It looks easy. It can be tricky. It is absolutely invaluable.”

[Evidence-Based Answers to Clinical Questions for Busy Clinicians. (2006). The Centre for Clinical Effectiveness, Monash Institute of Health Services Research, Melbourne, Australia, p. 2]

The PICOS Approach

P Population, Patient

I Intervention

C Comparison

O Outcome

S Study Design

P = Population/Patient

When defining this question component, consider the following patient characteristics:

Disease/condition, including the duration, localization, and type of symptoms

Age

Gender

Setting

Standard Diagnostic Criteria

Sample: Modern Medicine for

Treating Malaria

P (Population,

Patient)

Who are the

patients? Who is

affected? Any

exclusions?

Describe the

specific patient

population

characteristics

and/or context of

the disease

Children in Africa

(excluding

adults) suffering

from malaria

P (Population/Patient)

Considerations to Remember

Restrictions on populations/settings

should be based on a sound rationale –

important for Cochrane reviews to be

globally relevant

I = Intervention

When deciding on the intervention(s) that

will be present in a systematic review,

the following should be explicitly

described:

Type of intervention

Intensity of intervention

Frequency of intervention

Duration of intervention


Treating Malaria

I (Intervention) What is being

done? What

interventions

should be

evaluated?

Define the

intervention!

Modern medicine

(antibiotics)

I (Intervention)


Interventions can consist of: treatment,

diagnostic/screening test, exposure, or

prognostic factor

Should all variations be included?

How will co-interventions, or trials that

only include part of an intervention be

handled?

C = Comparison

Main alternative being considered

Intervention should be explicitly defined

Placebo

Standard therapy

No treatment

Another treatment

Usual care (“the gold standard”)


Treating Malaria

C

(Comparison)

What is the

alternative to the

intervention? How

effective are

different

interventions?

Traditional

medicine

(homeopathic

remedies)

C (Comparison)


Control groups

Inactive Control

Active Control

O = Outcome

When determining the desired/expected

outcomes of a systematic review, it is key to

consider the following:

Explicit outcome measures and tools

Standardized, validated, established outcome

measures appropriate for the disease condition

Focus on outcomes that are important to patients

Side effects (if known) should be included

Timing of outcome measures should be described


Treating Malaria

O (Outcome) What are the

relevant

outcomes? What

do you want to

accomplish,

measure,

improve? Define

specific outcomes

Malaria

prevention, death

reduction

O (Outcome)


Include all important outcomes (primary

and secondary)

Include adverse effects

Consider Economic Data

Do Not Include an outcome that is trivial

or meaningless to decision makers!

S = Study Design

The type of study design utilized is

dependent on the type of question

defined. The presence of bias with

different designs should be considered

before deciding which one is most suited

to the question being pondered

Source: Glossary of Terms in the

Cochrane Collaboration Version 4.2.5

May 2005

Types of Study Designs

(Interrupted) Time Series A research design that collects observations at multiple time

points before and after an intervention (interruption). The design attempts to detect whether the intervention has had an effect significantly greater than the underlying trend.

Case-Control Study A study that compares people with a specific disease or

outcome of interest (cases) to people from the same population without that disease or outcome (controls), and which seeks to find associations between the outcome and prior exposure to particular risk factors. This design is particularly useful where the outcome is rare and past exposure can be reliably measured. Case-Control studies are usually retrospective, but not always

Source: Glossary of Terms in the

Cochrane Collaboration Version 4.2.5

May 2005

Types of Study Designs

(continued)

Cohort Study An observational study in which a defined group of people

(the cohort) is followed over time. The outcomes of people in subsets of this cohort are compared, to examine people who were exposed or not exposed (or exposed at different levels) to a particular intervention or other factor of interest

Randomized Controlled Trial (RCT) An experiment in which two or more interventions, possibly

including a control intervention or no intervention, are compared by being randomly allocated to participants. In most trials one intervention is assigned to each individual but sometimes assignment is to defined groups of individuals (for example, in a household) or interventions are assigned within individuals (for example, in different orders or to different parts of the body)


Treating Malaria

S (Study

Design)

What is the best

study design to

answer the

question ?

Therapy =

prospective RCT;

Prevention =

RCTCohort

StudyCase

Control

S (Study Design)


Most reviews use RCT’s as a threshold

(RCTs are considered the least biased

form of evidence)

Cochrane and Campbell collaborations

may also take evidence from interrupted

time series

Class Exercise

Topic: Interventions to increase influenza

vaccination rates of the elderly in the

community and in institutions

Exercise: Interventions to Increase

Influenza Vaccination Rates

P (Population,

Patient)

Who are the

patients? Who is

affected? Any

exclusions?

Describe the

specific patient

population

characteristics

and/or context of

the disease

Age=adults, elderly,

seniors, NOT

children, NOT

adults <60)

Gender= male &

female

Setting=institution

(hospital, care centre)

vs. community

(home, public place)

Disease/Condition =

influenza



I (Intervention) What is being

done? What

interventions

should be

evaluated?

Define the

intervention

Patient

interventions;

Administrative

interventions;

Health care

workers (HCW)

interventions;

Societal

interventions



C

(Comparison)

What is the

alternative to the

intervention? How

effective are

different

interventions?

No alternative

intervention, other

than to observe the

effectiveness of

different interventions

Comparison of

influenza rates,

illness, mortality



O (Outcome) What are the

relevant

outcomes? What

do you want to

accomplish,

measure,

improve? Define

specific outcomes

Effects of

interventions on

both immediate

and long-term

changes in

influenza

vaccination rates,

and on outcomes

of interest



S (Study

Design)

What is the best

study design to

answer the

question ?

RCTs

cochrane workshop picos

Health & Medicine