asking answerable clinical question payam kabiri. md.phd

ASKING ANSWERABLE

CLINICAL QUESTION

Payam Kabiri. MD.PhD.

a five-step process for using an evidence-based approach in general practice

(1) define the problem

(2) track down the information sources you need

(3) critically appraise the information

(4) apply the information with your patients

(5) evaluate how effective this application of information is.

Clinical scenario

• The patient is a 77-year-old man admitted for dyspnea and fever. He fell ill 4 days ago with low-grade fever, chills, myalgias, rhinorrhoea and a non-productive cough. One day ago he developed dyspnea on exertion, purulent sputum, lateral chest wall pain with inspiration and a shaking chill. His general health is fairly good; he has had essential hypertension for 12 years, well controlled on diuretic therapy. He has not smoked.

• On examination, his respiratory rate is 28, his heart rate is 108 and his temperature is 39.2°C. He may have subtle cyanosis. His chest expands symmetrically, he has no prolongation of expiration and no wheezing. There is bronchophony and egophony in the left lower posterior lung field.

• Initial blood tests show leukocytosis and hyponatremia.

• The team suspects acute community-acquired pneumonia with hypoxemia, and plans chest radiographs, sputum studies, supplemental oxygen and antimicrobial therapy.

• what questions you have about this case?

A medical students’ questions:

1. What microbial organisms can cause community-acquired pneumonia?

2. How does pneumonia cause egophony?

3. What is the incidence of community-acquired pneumonia?

• Notice that the students’ questions ask for general or “background” knowledge about pneumonia, the disorder that presumably explains much of this patient’s acute illness.

a.s

Background Ask for general knowledge about a disorder two essential components:

• A question root (who, what, where, when, how)

• A disorder, or an aspect of a disorder

Type of question

A practitioners’ questions:• In this patient are any clinical findings sufficiently

powerful to confirm or exclude pneumonia?• In this patient is a chest radiograph necessary for

the diagnosis?• In this patient is the probability of Legionella

infection sufficiently high to warrant considering covering this organism with the initial antibiotic choice?

• In this patient , do clinical features predict outcome well enough that as a “low risk” patient can be treated safely at home?

• these questions ask for specific knowledge about diagnosis, prognosis, and treat the patients with pneumonia, which might be called “foreground” knowledge.

Type of question

Foreground1.The patient and/or problem

2.The main intervention (defined very broadly, including an exposure, a diagnostic test, a prognostic factor, a treatment, a patient perception, and so forth)

3.Comparison intervention(s)

4.The clinical outcome(s) .

Foreground Questions

Background Questions

Experience with Condition

Common Types of question and study design

– Causation / Etiology

– Diagnosis

– Therapy

– Prognosis

A Good Question should be:

• Relevant - Will the answer matter?

• Answerable - Can the question be

answered by research data?

• Clear - unambiguous

• Worthy - Is the answer worth the work?

Question components : PICO

• What types of Participants?

• What types of Interventions?

• What types of Comparison?

• What types of Outcomes?

Participants

Intervention Group (IG) & Comparison Group (CG)

Outcome

IG

CG

+ -+

- DC

BA

Representative?

Allocation?

Selection?

Maintenance of allocation?

VALIDITY

comparable groups?treated equally?compliant?

Ascertainment?

Measurements blind subjective? OR objective?

QUESTION:

Concealed allocation?(Randomised)

Measurement of outcomes?

DESIGN:

What types of participants?

Disease or condition of interest Potential co-morbidity Setting Demographic factors

What types of intervention?

Type of treatment Type of diagnostic test Type of causative agent Type of prognostic factor

What types of outcomes?

• For treatment include all outcomes important to people making decisions to define success of therapy

• For prognosis, outcome is the chosen endpoint of the disease

Patient oriented outcomes

• Mortality/survival

• Disease free period

• Quality of life

• Work absenteeism

• Disability/ Duration and severity of illness

• Pain

deciding which question to answer first

1.What is the most important issue for this patient now?

2.Which question, when answered, will help me most?

3.Most likely recur in my practice?

WHY BOTHER FORMULATING QUESTIONS CLEARLY?

Our own experiences suggest that well-formulated questions can help in seven ways:

1. They help us focus our scarce learning time on evidence that is directly relevant to our patients’ clinical needs.

2. They help us focus our scarce learning time on evidence that directly addresses our particular knowledge needs, or those of our learners.

3. They can suggest high-yield search strategies (see Ch. 2).4. They suggest the forms that useful answers might take (see Chs 3–

6).5. When sending or receiving a patient in referral, they can help us to

communicate more clearly with our colleagues.6. When teaching, they can help our learners to better understand the

content of what we teach, while also modeling some adaptive processes for lifelong learning.

7. When our questions get answered, our knowledge grows, our curiosity is reinforced, our cognitive resonance is restored, and we can become better, faster, and happier clinicians

POEM: Patient Oriented Evidence that Matters

DOE: Disease Oriented Evidence

Comparing DOES and POEMs

Example

Disease-OrientedEvidence

Patient-OrientedEvidence that

Matters Comment

AntiarrhythmicTherapy

Drug X PVCson ECG

Drug X increasesmortality

POEM studycontradicts DOEstudy

Antihypertensivetherapy

Antihypertensivetherapy BP

Antihypertensivetherapy mortality

POEM agreeswith DOE

ProstateScreening

PSA screeningdetects prostatecancer early

? whether PSAscreening mortality

DOE exists, butthe importantPOEM isunknown

Example 1A TV programme has highlighted a hospital

in Suffolk in which a stroke unit has been set up that specialises in the treatment of patients who have suffered strokes. The hospital trust wants to know about the effectiveness of stroke units in terms of lives saved before deciding whether to invest in one.

Patient

Or Problem

Intervention Comparison Outcomes

Patient

Or Problem

Intervention Comparison Outcomes

Patients who have suffered strokes

Patient

Or Problem

Intervention Comparison Outcomes

Patients who have suffered strokes

Stroke units

Patient

Or Problem

Intervention Comparison Outcomes

Patients who have suffered strokes

Stroke units Normal hospital

care

Patient

Or Problem

Intervention Comparison Outcomes

Patients who have suffered strokes

Stroke units

Normal hospital

care

Lives saved

Or

Do stroke units save lives ?

Example

• A acute cough is a common reason for patients to consult their GP. The causes of acute cough varies a lot. the treatment often includes antibiotics.

• The effectiveness of Abx is questionable and there has been a great deal of concern about bacterial resistance from over-prescribing.

Patient

Or Problem

Intervention Comparison Outcomes

Patient

Or Problem

Intervention Comparison Outcomes

Acute Cough in primary

care setting

Patient

Or Problem

Intervention Comparison Outcomes

Acute Cough in primary

care setting

Antibiotics

Patient

Or Problem

Intervention Comparison Outcomes

Acute Cough in primary

care setting

Antibiotics No antibiotics

Patient

Or Problem

Intervention Comparison Outcomes

Acute Cough in primary

care setting

Antibiotics No antibiotics

Duration and

severity of illness

Patient: Acute Cough in primary care setting

Intervention: Antibiotics

Comparison: No antibiotics

Outcomes: Duration and severity of illness

Clinical trials

• The foundation of nursing practice– Whether you like it or not.... :‑).– Take a set of patients

• RANDOMLY allocate them,– half to one therapy, half to the other.– See what happens

• Compare the two groups

Example

• My 1 yr old just had a febrile seizure - what will happen to her?

Example

• Patient: In children 6mo-6yrs who have had

•Intervention( Exposure): a first febrile seizure, what is

•Outcome: the likelihood of recurrent febrile seizures; epilepsy; neurologic damage?

Cohort studies

• Typical question ‑– What are the consequences of exposure to dioxins?– What health effects are due to the nuclear industry?– What effect does parental poverty have on later family

formation by children?– Is measles vaccine safe?– What is the long term survival of …

•A 44-year-old woman with recently diagnosed ovarian cancer presents to the emergency room with dyspnea and inspiratory chest discomfort. •The ventilation-perfusion scan is read as “indeterminate.” •The emergency room doctor asks your advice “now that embolism has been ruled out.”

Example

•When compared with pulmonary angiography, how well does an indeterminate result of a ventilation-perfusion scan rule out pulmonary embolism in a patient with a high pretest probability?

Surveys/Cross‑sectional studies

• Typical questions ‑ – What proportion of people smoke?– Are male medical students more likely to drink too

much than females?– Is the risk of spina bifida higher in poor people than

in rich people?– What is the value of positive V/Q scan…

• Patient: Woman with Ovarian cancer,dyspnea

•Intervention: Ventilation-Perfusion scan

•Outcome: Pulmonary Embolism

•Comparison: Pulmonary Angiography

What if too many questions arise?

• patients may have several active problems – possible questions about diagnosis, prognosis, therapy for each

problem

– your questions may be too numerous to even ask, let alone answer.

• What is the most important issue for this patient now?

• Which question, when answered, will help me most?

• Most likely recur in my practice?

Well-formulated questions guide the whole EBM process

• Key components of the question are types of participants, interventions, and outcomes

• study designs should limit bias

• Questions may be broad of narrow

The Sensitive Question

• Covers large areas of patient care

– inclusive populations or multiple subgroups

– covers all possible treatment options

• Covers all the available evidence

• Covers all potentially important outcomes

What is the Best Treatment for Zoster?

• What is the most cost-effective treatment for zoster if we consider pain reduction, quality of life and prevention of post-herpetic neuralgia (and take into account adverse effects and dropouts)?

The Sensitive Question

• Relevance: very high if appropriate outcomes

selected: heterogeneous results if …

Validity: dependent on available data but often

very low

• Work: can be time consuming

The Specific Question

• Covers small areas of patient care

– specific well-defined populations

– specific treatment options

• Covers only the best available evidence

• Focus only on outcome of main interest

What is the Best Treatment for Zoster?

• Is famciclovir effective at preventing postherpetic neuralgia (defined as pain 3 months after rash healing) in otherwise healthy patients aged 60-70 who present within 48 hours of zoster rash, compared with placebo?

The Specific Question

Generalisability

Biased conclusion

Reviewer bias

Broad or narrow questions?

• Broad– Do Qinghaosu drugs reduce mortality and

morbidity in people with severe malaria?

• Narrow– Do Qinghaosu suppositories reduce mortality in

children with cerebral malaria?

The Bottom Line

“We may not have all the right answers, but we need to

find and verify those that do exist; for the rest, we

need to ask the right questions.”

Broad or narrow questions?

• Broad

– Do drug X reduce mortality and morbidity in people with severe malaria?

• Narrow

– Do drug X suppositories reduce mortality in children with cerebral malaria?

THANK YOU