Download Type of Study

Information at Point of Need
“We believe the best use of
information technology provides
health care information at the
point of need and in the manner
in which it can best be utilized.”
©Sandra A. Martin
Source: Martin, S. A., Shreeve, S. & Prislin, M. (1999). Development of a longitudinal patient-care
oriented informatics curriculum featuring web-based instructional and assessment tools. Association of
American Medical Colleges Annual Meeting.
Background vs. Foreground
Questions
Asking questions about your proposed topic
helps to clarify your knowledge gap
Type of question helps to determine which
sources are most likely to have the answers
you need
Background Questions
Generally ask who, what, why, where or how
about a single concept
Examples:
What are the contraindications for the use of
timolol to treat glaucoma?
What are the risk factors for glaucoma?
Answers to Background
Questions
Require general knowledge of disease and
therapeutic processes
Quickest places to find answers in drug
monographs and review articles
Foreground Questions
Usually compare two or more concepts –
drugs, treatments, tests, prognosis of two
groups, harms or benefits of two
approaches, etc.
Example:
Is latanoprost as effective as travoprost or
bimatoprost in achieving 24-hour control of
IOP in patients with POAG?
Answers to Foreground
Questions

Require precise information about complex
issues
 Sources should provide current, original
clinical research data
– Pub Med / The Cochrane Library
‫جستجوی شواهد‬
‫برای تهیه راهبرد جستجو‪ ،‬ابتدا اجزای پیکو را مشخص‬
‫میکنیم‪.‬‬
‫مترادف هر یک از اجزا را پیدا میکنیم‪.‬‬
‫از ترکیب اجزای پیکو راهبرد(های) جستجو را تهیه‬
‫میکنیم‪.‬‬
‫‪8‬‬
‫جستجوی شواهد‬
P
I
Filter
(P AND I AND C AND O)
C
9
O
9
)‫(ادامه‬

‫جستجوی شواهد‬
In children with colds, are zinc lozenges safe and effective for
relief of cold symptoms?
Question part
Question term
Population/problem Child;
Cold
Synonyms
Children, youth;
Common cold, rhinovirus
Lozenges, Zinc acetate,
Zinc gluconate
Intervention
Zinc
Comparator
No zinc
–
–
–
Outcome
10
)‫(ادامه‬
‫جستجوی شواهد‬
‫ راهبردهای جستجو به وجود‬،‫از ترکیب واژههای مختلف‬
:‫میآید‬
(Population/Problem OR synonym1 OR synonym2…) AND
(Intervention OR synonym1 OR synonym2…) AND
(Comparator OR synonym1 OR synonym2…) AND
(Outcome OR synonym1 OR synonym2…)
11
)‫(ادامه‬
‫جستجوی شواهد‬
Child AND Cold AND Zinc
(Child OR Children OR youth) AND (Cold OR Common cold OR
Rhinovirus) AND (Zinc OR Zinc acetate OR Zinc glocunate)
12
‫جستجوی شواهد‬
‫انواع سؤال بالينی‬
‫‪‬‬
‫عامل بیماری –‬
‫تشخیص –‬
‫درمان –‬
‫پیشگیری –‬
‫پیشآگهی –‬
‫‪13‬‬
‫(ادامه)‬
‫جستجوی شواهد‬
‫انواع مطالعه‬
‫(ادامه)‬
‫‪‬‬
‫کارآزمایی بالینی –‬
‫مطالعه کوهورت (همگروهی) –‬
‫مطالعه مورد‪ -‬شاهدی –‬
‫مطالعه مقطعی –‬
‫مشاهده بالینی (گزارش موردی‪ ،‬گزارش سری موارد) –‬
‫‪14‬‬
‫جستجوی شواهد‬
‫‪15‬‬
‫(ادامه)‬
)‫(ادامه‬
‫جستجوی شواهد‬

‫نوع سؤال و نوع مطالعه‬
Question
Best study designs
INTERVENTION
Randomized controlled trial (RCT)
AETIOLOGY AND
RISK FACTORS
FREQUENCY
AND RATE
DIAGNOSIS
PROGNOSIS AND
PREDICTION
Randomized controlled trial (RCT)
Cohort study
Case-control study
Cohort study
Cross-sectional study
Cross-sectional study with random or
consecutive sample
Cohort/survival study
16
)‫(ادامه‬
Level
Intervention
I
Least
Biased
‫جستجوی شواهد‬
Diagnosis
Etiology
Systematic review of Systematic review of Systematic review of Systematic review of
level II studies
level II studies
level II studies
level II studies
II Randomized
controlled trial
Cross-sectional
study among
consecutive
presenting patients
II One of the following: One of the
I  Non-randomized
following:
experimental study  Cross-sectional
 Analytical
study among
observational studies non-consecutive
patients
 Diagnostic casecontrol study
Case series
I Case series
V
Most
biased
Prognosis
Inception cohort
study
Prospective cohort
study
One of the following:
 Untreated
control patients
in a randomized
controlled trial
 Retrospectively
assembled cohort
study
Case series. or a
cohort study of
patients at
different stages of
disease
One of the following:
 Retrospective
cohort study
 Case-control study
A cross- sectional
study
17
‫جستجوی شواهد‬
‫(ادامه)‬
‫برای پاسخ به یک سئوال بالینی همه مطالعات ارزش یکسانی‬
‫ندارند‪.‬‬
‫رتبهبندی مطالعات از نظر احتمال سوگیری و امکان‬
‫پاسخدهی بهتر به انواع سؤاالت‪ ،‬به ما کمک میکند برای‬
‫پاسخ به سؤال خود بهترین شواهد ممکن را جستجو و پیدا‬
‫کنیم‪.‬‬
‫‪18‬‬
)‫(ادامه‬
‫جستجوی شواهد‬
‫سازماندهی شواهد در پایگاههای دادهای‬
Systems
Computerized decision support
systems
Synopses
Evidence-based Journal abstracts
Syntheses
Cochrane reviews
abstracts
Single Studies
Original published
articles
19
The Case
We will focus on the following patient case:
Mr. J. is a 70-year-old African American man with a history of acute
myocardial infarction (MI) six weeks ago. He appears to be doing well
on medical therapy (including aspirin, beta blocker, ACE inhibitor, and
statin), though post-MI echocardiography has shown a low left
ventricular ejection fraction (LVEF) of 30%. Mr. J. is very close to his
grandchildren and reports that his eldest granddaughter just got into law
school. He is concerned that, given the state of his heart,
he will not survive to see her graduate.
Mr. J's physician tells you that several studies have investigated
whether prophylactic placement of an implantable defibrillator can
reduce mortality in patients such as Mr. J. who have problems with
ejection fraction following an MI. She tells you to find evidence that
would indicate whether or not Mr. J. might benefit from implantation of
a defibrillator.
You are asked to do a PubMed search and bring the answer to morning rounds.
Formulating your Question
One of the most important steps in doing a PubMed search is
creating a focused question. PubMed includes over 18 million
citations, but not all of them will meet your information needs. Think
about your topic and formulate a specific question that will help you
retrieve and identify relevant information. The following framework,
often referred to as PICO or PICOTT, helps you to identify the
important elements of a question (the who, what and why).
Patient Problem – Describe the primary condition or patient's
problem.
Intervention, diagnostic test, prognostic factor, or exposure - What
treatment, test, or exposure are you considering?
Comparison - What are you comparing this to? (You don't always
have an active comparison.)
Outcome - Describe what you and the patient want to have happen.
TT - Type of Question/Type of Study
Type of Question and Study
You also need to think about the type of question you are asking. Some types of questions may require a
certain type of study [PDF].
For example, if you are interested in whether a drug is effective in treating a particular disease, you would
look for randomized controlled trials.
Type of Question
Type of Study*
Therapy-- how to select treatments that do more
good than harm and that are worth the efforts and
costs of using them
RCT (randomized controlled trial)> prospective cohort
Can also be answered by a meta-analysis or systematic review
Diagnosis-- how to select and interpret diagnostic
tests, in order to confirm or exclude a diagnosis,
based on their precision, accuracy, acceptability,
expense, safety, etc.
prospective, blind comparison to a gold standard
Prognosis-- how to estimate the patient's likely
clinical course over time and anticipate complications
of disease
cohort study > case control > case series
Etiology/Harm-- how to identify causes for disease
(including iatrogenic forms)
RCT** > cohort > case control > case series
PICOTT
Using our case, we can describe the patient problem, intervention,
comparison, and outcome and note the type of question and the
corresponding type of study.
PICOTT:
Our Case:
male, African American, history of
Patient Problem
myocardial infarction and low left
ejection fraction
Intervention
implantable defibrillator
Comparison
none
Outcome
reduce risk of death; reduce mortality
Type of Question
therapy
Type of Study
randomized controlled trial
Forming the Clinical Question
Your clinical question would be something like: In
patients with a history of acute MI and low left
ejection fraction, will an implantable
defibrillator help reduce mortality?
Formulate the Strategy using Key Concepts
Now, what would you search? Using the PICOTT framework helps you set up your
search strategy. You don't always need to include all concepts in a search such as
race, gender, or age. But having these concepts defined in the PICOTT will help you
choose the most relevant articles later on. (Even if you think age is important here,
you don't need to include it in your search at the beginning; rather wait until the end
to limit by age group on the Limits page.)
*This is a therapy question. We will get at the concept of therapy by searching for the
type of study that correlates with it (RCT).
PICOTT:
Our Case:
Key Concepts:
male, African American, history
myocardial infarction
Patient Problem of myocardial infarction and low
low left ejection fraction
left ejection fraction
Intervention
implantable defibrillator
implantable defibrillator
Comparison
none
reduce risk of death; reduce
Outcome
mortality
mortality
Type of Question
therapy
*
Type of Study
randomized controlled trial randomized controlled trial
Search strategy
myocardial infarction OR low left ejection fraction
AND implantable defibrillator AND mortality
Exercises: PICO scenarios
Medical students
Group 1
Aspirin for the primary thrombosis prevention
in the antiphospholipd syndrome
The accuracy of single serum progesterone
measurement in the diagnosis of ectopic
pregnancy
Antibiotics versus placebo for postoperative
infection after appendicectomy
Group 2
In diabetic patients does aspirin prevent
CVD
In elderly patients does MD intervention
therapies reduce the incidence of falls
In patients with suspected heart failure does
BNP accurately predict disease compared
to the gold standard
Group 3
Does Steroid Treatment improve renal recovery
in patients with induced acute interstitial
nephritis
Is early compared to late haemodialysis better
for survival in critically ill patients with ARF
( acute renal failure)
Does pre operative compared to post operative
chemo and radiotherapy improve survival in
rectal cancer patients with resectable disease
Group 4
Does a statin reduce CVD in Middle aged men with no
IHD, but a high cholesterol
What is the evidence that every pregnant women needs
to have folic acid to reduce neural tube defects
Does CPAP improve mortality in pulmonary odema
What is the evidence goserelin reduces chronic pelvic
pain
Group 5
Is aspirin effective in primary prevention of CVD
in diabetics
Is vitamin c effective for the symptoms of the
common cold
In patients with FH of thalassaemia does using a
risk counselling tool increase number going to
screening
Antibiotics versus placebo for postoperative
infection after appendicectomy
PICO Exercises/ nursing students
A 72 y/o male with osteoarthritis wants to take glucosamine and
chondroitin sulfate instead of other meds. Is there any evidence of
effectiveness?
A women in her mid 40s with a family history of breast cancer is
scheduling her yearly breast exam. Should an MRI or a
mammogram be scheduled?
A nurse in the ICU asks about the care of patients with head injuries.
She’s wondering if elevating the head of the bed 30 degrees will
reduce intracranial pressure.
John is 3 years old, has an ear infection and hates taking medicine.
He’s already taken the antibiotic for 6 days and is feeling better.
His parents want to know if they can stop. Is the short course (< 7
days) as effective as the long course (14 days) in treating otitis
media in children?
You have an infant with suspected congenital heart disease and order an
MRI. The parents request an echocardiogram. Which test should be
performed or both?
In children with asthma, 2mg/kg of prednisone is commonly used. In other
countries the usual dose is 1mg/kg. Which is more effective in reducing
length of exacerbations?
A nurse in the PACU (post-anesthesia care unit) is interested in ways to
decrease the use of pain medication in post-op patients. She’s wondering
if classical music or guided imagery might be efficacious.
A nurse in the ICU asks about the care of patients with head injuries. She’s
wondering if elevating the head of the bed 30 degrees will reduce
intracranial pressure.
John is 3 years old, has an ear infection and hates taking medicine. He’s
already taken the antibiotic for 6 days and is feeling better. His parents
want to know if they can stop. Is the short course (< 7 days) as effective
as the long course (14 days) in treating otitis media in children?
Thanks