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Methodological Issues in Systematic Reviews: Formulating Questions. Thomas A Trikalinos , MD, PhD Co-Director, Tufts Evidence-based Practice Center. Author has no actual or potential conflicts of interest in relation to this activity. Asking the right question. We will cover.

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methodological issues in systematic reviews formulating questions

Methodological Issues in Systematic Reviews: Formulating Questions

Thomas A Trikalinos, MD, PhD

Co-Director, Tufts Evidence-based Practice Center

Author has no actual or potential conflicts of interest in relation to this activity

we will cover
We will cover
  • PICO(TS) approach to generate answerable research questions
  • Analytic framework to identify potential questions
  • Other considerations in formulating questions
systematic review protocol
Systematic review protocol
  • Well focused study question [ PICO(TS) ]
  • Identification of studies (studies design, source, search strategy)
  • Eligibility criteria (study, patient, and disease characteristics, treatments, outcomes)
  • Data extraction (definition of outcomes, quality assessment)
  • Data summary and analysis (outcomes used, intention to treat)
pico ts approach to formulating answerable research questions
PICO(TS) approach to formulating answerable research questions
  • Population (participants)
  • Intervention
  • Comparator
  • Outcome
  • Time (duration)
  • Study design (experimental / observational, N)
diagnostic test research question test performance
Diagnostic test research question- test performance -

Condition of

interest

Setting

population

Outcomes

Intervention

What is the diagnostic accuracy of sestamibi scan to detect ACI in patients in the ED?

Adults with symptoms suggestive of acute cardiac ischemia and non-diagnostic ECG seen in the ED

sensitivity

specificity

  • - AMI
  • unstable angina

technetium-99m sestamibi scan

Comparator

diagnostic test research question clinical impact
Diagnostic test research question- clinical impact -

Condition of

interest

Setting

population

Outcomes

Intervention

What is the clinical impact of sestamibi scan to detect ACI in patients in the ED?

Adults with symptoms suggestive of acute cardiac ischemia and non-diagnostic ECG seen in the ED

False negative discharges from the ED

False positive admits

Deaths

  • - AMI
  • unstable angina

technetium-99m sestamibi scan

Comparator

we will cover1
We will cover

PICO(TS) approach to generate answerable research questions

Analytic framework to identify potential questions

Other considerations in formulating questions

approach to de constructing research question
Approach to (de)constructing research question
  • Question of interest is often over-arching and not directly addressable
    • Ex. How to manage hypercholesterolemia?
  • Need to break it down into answerable subunits
  • Multiple questions frequently needed
  • Final answers (recommendations) typically involve additional information, balancing the benefits and harms, feasibility, costs, etc
simplified evidence model linking biological effects intermediate and health outcomes
Simplified Evidence Model Linking Biological Effects (intermediate) and Health Outcomes
we will cover2
We will cover

PICO(TS) approach to generate answerable research questions

Analytic framework to identify potential questions

Other considerations in formulating questions

problems defining interventions and comparators

Problems defining interventions and comparators

Exercise training

AND OPTIONALLY:

“Conventional” care

Inspiratory muscle training

Education

Vs

Breathing exercises

Psychosocial/ behavioral interventions

Pulmonary rehabilitation vs conventional care

AHRQ Evidence Report/Technology Assessment

Pulmonary rehabilitation for COPD, 2007; http://www.ahrq.gov

problems in coming up with questions
Problems in coming up with questions
  • Sometimes you don’t know what should be the question because there is not yet agreement among investigators about the meaning
  • Pre-emptive analgesia: different investigators have different ideas about what it is
  • Solution: Rather than pick an arbitrary definition, try to group what has been studied into several similar categories and address them, this will provide evidence of the spectrum of mechanisms
  • Question: What is the effect of timing of analgesics on post-op requirements of pain medication and patient outcomes?
problems with diagnosis
Problems with diagnosis
  • varying definitions (lack of an adequate reference standard)
  • different levels of rigor
  • tradeoffs between rigor and real world practice (sinus puncture to diagnose sinusitis vs. actual clinical practice: efficacy vs. effectiveness)
management of clinically inapparent adrenal mass adrenal incidentaloma the evidence report

Management of Clinically Inapparent Adrenal Mass(Adrenal Incidentaloma):The Evidence Report

NIH State-of-the-Science ConferenceFebruary 4, 2002

incidentaloma is not a disease
Incidentaloma is NOT a disease

The prevalence of this phenomenon and the pathologies and their likelihood will depend on:

  • Patients with known cancers or not
  • Presenting signs and symptoms
  • Patient’s age and sex
  • Biochemical activity findings
  • Initial diagnostic test used (CT, US, MRI)
  • Size of the mass (lower limit)
what are the pathologies reported among adrenal incidentaloma
Adenoma

Adrenocortical carcinoma

Angiomyelolipoma

Cyst

Epithelial carcinoma

Hyperplasia

Hematoma

Lymphoma

Metastases

Myelolipoma

Neurinoma

Pheochromocytoma

Regenerative hepatic nodule

Renal angiomyolipoma

Retroperitoneal fibrosis

. . . more

What are the pathologies reported among adrenal incidentaloma?
issues in formulating a question
Issues in formulating a question
  • Narrow versus broad (for individuals/ subgroups or entire population)
  • Clinically meaningful and useful (based on sound biological and epidemiological principles)
  • Very broadly defined questions may be criticized for mixing apples and oranges
  • Very narrowly focused questions have limited generalizability and sometimes may lead to biased interpretations / conclusions
benefits of getting the questions right at the start
Benefits of getting the questions right at the start
  • Improves clarity of the problem
  • Facilitates subsequent steps of the systematic review
  • Helps select right kind of studies for review
  • Anticipates issues, resource needs
  • Improves efficiency, reduces needs to revisit questions / re-review papers, minimizes wasted efforts
summary
Summary
  • PICO(TS) method is a very useful technique to formulate answerable research questions
  • Analytic framework can be useful to visualize and think about related issues
  • Defining criteria
  • Biologically meaningful
  • Question and criteria guide the entire systematic review process
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