Questions and Outcomes

Self-Study ModuleJohn Epling, MD, MSEd

Preventive Medicine ProgramSUNY-Upstate Medical University

Acknowledgements

• This presentation reviews material from: – the Evidence-Based Medicine Working Group

• http://www.cebm.net/• http://ktclearinghouse.ca/cebm/

– the Information Mastery Working Group• http://www.medicine.virginia.edu/clinical/

departments/familymed/information_mastery

Questions and Outcomes

• Two topics to start our course with:– Clinical Questions

• How we know what we don’t know…

– Outcomes• What are we striving for?

• Click through these slides – there are definitions and examples for all the concepts. You’ll practice what you learned in class.

Clinical Questions

• Teach thy tongue to say 'I do not know,' and thou shalt progress.– Maimonides

Why talk about Questions?

• Because most of medical school is composed of asking YOU questions…

• We don’t emphasize enough teaching you the reasons and ways to ask questions…

• Questions help us be specific about how much and what we don’t know…

• They can also help us efficiently fill our knowledge deficits…

Two types of Questions

• Background

• Foreground

Background Questions

• Useful when you don’t have ANY knowledge about a topic

• Non-focused, general knowledge questions

• Think Stem + Clinical Topic– Stem = What is, Why do, How does…– Clinical Topic – the disease/condition of

interest

Background Questions

• Examples:– What is atrial fibrillation?– What are the causes of dyspnea?– What are the treatment options for deep vein

thrombosis?

• NOT a Background Question:– Should I use unfractionated heparin or low-

molecular weight heparin for a patient with deep vein thrombosis? (too specific, comparing therapies)

Foreground Questions

• Useful when you know about a topic, but you’re asking about a specific clinical comparison or test or detail about that topic.

• Think: PICO– P – patient/population– I – intervention/exposure/diagnostic test– C – comparison/no exposure/gold standard– O – outcome of interest/diagnosis

Foreground Questions

• There are four main types of foreground questions:– Therapy questions – comparing two or more

interventions for a condition– Etiology/Harm – looking for an association

between an exposure and an outcome– Diagnosis – comparing a new diagnostic test

to the reference standard test– Prognosis – given a condition, does a certain

factor portend a worse prognosis?

Therapy Questions

• Example (Using the PICO format)– In patients with deep vein thrombosis (DVT),

does unfractionated heparin vs. low-molecular weight heparin lead to decreased recurrence of DVT?

• P – patients with DVT• I – unfractionated heparin• C – low molecular weight heparin• O – recurrence of DVT

Therapy Questions

• Example:– In a population at risk for H1N1 influenza, does a new

H1N1 vaccine (versus no vaccine) decrease disease rates?

– In adults, does colorectal cancer screening (versus no screening) decrease mortality?

• NOT a Foreground Therapy Question:– How is influenza treated in adults? (too broad,

looking for treatment options, not comparing two or more for their effect on outcomes)

Diagnostic Test Questions

• These compare the accuracy of a new diagnostic test with that of the “reference standard” (the true confirmatory test) for the condition. The outcome is the diagnosis.

• Example (using PICO):– In patients in whom acute appendicitis is suspected,

does CT scan, as compared with exploratory laparotomy, diagnose appendicitis?

• P – pts with abdominal pain and poss appendicitis• I – CT scan• C – exploratory laparotomy (surgery, the reference

standard)• O – diagnosis of appendicitis

Diagnostic Test Questions

• Example:– In patients with a history of recent chest pains, does

stress echocardiography versus cardiac catheterization diagnose coronary artery disease?

• NOT a diagnostic test question:– In patients presenting to the ED with dyspnea, does

the use of a beta-natriuretic peptide test result in decreased morbidity and hospital stay?

– (tricky, the question is about a diagnostic test, but it is about how the use of the test alters clinical outcomes…not how well it diagnoses the disease)

Etiology/Harm Questions

• Useful to determine if one or more risk factors/exposures makes a clinical outcome more likely.

• Example with PICO:– In adults, does cell phone use (versus no cell phone

use) increase the risk of brain cancer?• P – adults• I – cell phone use (exposure…you may want to define a

certain amount of exposure as qualifying• C – no cell phone use (or below the certain amount)• O – brain cancer rates

Etiology/Harm Questions

• Example: In previously healthy children, does vaccination with MMR vaccine increase the risk of autism?

• Example: In adults with high risk of coronary heart disease, does exposure to vitamin E reduce the risk of coronary events?

• NOT an etiology question: What are the causes of autism? (too broad…although several etiology questions might provide the evidence to answer this some day)

Prognosis Questions

• Useful to determine which factors change the prognosis of a given disease.

• Example (using PICO): In patients with diabetes, does the development of neuropathy portend a greater mortality risk?– P - patients with type 2 diabetes,– I – development of neuropathy– C – not developing neuropathy– O –greater risk of mortality

Prognosis Question

• Examples: In patients with coronary heart disease, does an episode of CHF lead to reduced overall quality of life?

• NOT a prognosis question:– In diabetics, does smoking lead to a greater

risk of neuropathy? – (while the difference between harm and

prognosis questions is sometimes slight, this is really asking about a risk factor rather than a clinical development)

Questions about Questions?

• There you have it.• Background Questions – used when you need a

general review of a given topic.– They’re best answered with review articles from

trustworthy sources (we’ll talk about this later)

• Foreground Questions – used when you have a focused, clinical question– Look to original research (or structured synopses of

original research) for these answers (we’ll talk about these later too!)

Quick Break!

• Get up and stretch, get that second (or seventh) cup of Starbucks™, and then press on!

Outcomes

• All studies have outcomes…That’s what the study authors want to see change in as a result of the intervention or the exposure.

• Outcomes can be any definable clinical condition – a lab test result, a diagnosis, reaction or opinion, life or death, etc.

Outcomes

• For our purposes, we can divide outcomes into those that are PATIENT-ORIENTED and those that are DISEASE-ORIENTED.

• Patient-Oriented – these are outcomes that patients can identify with: life/death, sickness events (heart attacks, strokes), hospitalizations, disability, symptom rates, etc.

• Disease-Oriented – everything else – especially numbers – HgbA1c or lipid levels, blood pressure numbers.

Outcomes

• Frequently, in research, we look for “proxy measures” of disease – if we can prove that a high blood pressure is associated with mortality, then we can assume that lowering that blood pressure will reduce mortality.

• That just ain’t necessarily so – the body is complex, our interventions have side effects and there may be unintended consequences.

Outcomes

• Examples of proxy outcomes that failed:– CAST – we assumed that treating ventricular

dysrhythmia after a heart attack was a good thing…but the treatment was worse than the disease.

– Womens’ Health Intiative – we improved cholesterol, bone density and possibly Alzheimer’s with estrogen in post-menopausal women, but not until the better trial was performed did we realize we were causing disease.

Outcomes

• So, we, as busy clinicians, should try to find all the Patient-Oriented Evidence we can. By doing so, we can avoid hasty or premature conclusions about how the body and our treatments work.

• When faced with Disease-Oriented Evidence, we must use caution in interpreting its results, and look for more Patient-Oriented results (elsewhere in the literature, or in the future from better studies)

Outcomes

• When we’re evaluating the medical literature, outcomes aren’t the only important criteria, but focusing on Patient-Oriented outcomes can help us avoid overtreating based on preliminary findings.