Principles of evidence based medicine: Summary

To Improve quality care through the identification and promotion of practices that work, and the elimination of those that are ineffective or harmful.

EBM demands that the effectiveness of clinical interventions, the accuracy of diagnostic tests, and the power of prognostic markers should be scrutinised and their usefulness proven.

Clinicians should be open to try new scientifically proven methods and discard those that aren't. 

It's important that clinicians develop key EBM skills including the ability to find, critically appraise, and incorporate sound scientific evidence in their own practice.

The practice of EBM should start with a well formulated clinical question.

A good question should be clear, directly focused on the problem and answerable by medical literature research.

 A good clinical question has 3-4 components:

• Patient or problem
• Intervention, test or exposure of interest
• Comparison interventions (if applicable)
• Outcome(s)

Question should then be made using the PICO (Patient, Intervention, Comparison, Outcome) or PIO (Patient, Intervention, Outcome) format .

A 4 month old baby is admitted with viral bronchiolitis. The baby's symptoms worsen and you wonder if corticosteroids might help the child improve and reduce the length of hospital stay.

The key components of your clinical question would be:

Patient: 4 month old baby with viral bronchiolitis.

Intervention: corticosteroids.

Comparison: no corticosteroids.

Outcomes: clinical score, length of stay.

Clinical question may be formulated as follows:

In a 4 month old baby with viral bronchiolitis, does the administration of corticosteroids improve clinical score and reduce length of hospital stay, or not?

The next step is to seek relevant evidence that will help you answer the question.

Sources are:

1. Traditional methods (textbooks, journals).
2. Ask an expert. (answer quality will vary)
3. Summarised clinical evidence (BestBets).
4. Electronic bibliographic databases(Cochrane Library databases, PUBMED, MEDLINE, EMBASE, and CINAHL).

To find relevant articles fast:

• Use Boolean operators "AND" and "OR"
• Example:

1. Viral bronchiolitis
2. Corticosteroids OR steroids OR glucocorticoids OR prednisolone OR dexamethasone
3. Clinical score OR hospital stay
4. (1) AND (2) AND (3).

After obtaining relevant articles on a subject, the next step is to appraise the evidence for its validity and clinical usefulness.

Research evidence may be appraised with regard to three main areas:

1. Validity
2. Importance
3. Applicability to the patient or patients of interest.

Critical appraisal provides simple, structured methods for assessing research evidence in all three areas.

Appraisal skills may be learnt within small tutorials, workshops, interactive lectures, and at the bedside.

Tools for appraising research articles are available. Like the Critical Appraisal Skills Programme (CASP).

After critically appraising the evidence, we then decide whether that evidence can be applied to our individual patient or population, taking into account the patient’s own personal values and circumstances.

Both efficacy and risks should be fully discussed with the patient or parents, or both, to allow them to make an informed decision.

This approach is consistent with the EBM principle: the integration of good evidence with clinical expertise and patient values.

This decision should also take into account the feasibility and availability of the treatment. 

As we incorporate EBM into routine clinical practice, we need to evaluate our approach at frequent intervals and to decide whether we need to improve on any of the four steps discussed above.

We need to ask whether we are formulating answerable questions, finding good evidence quickly, effectively appraising the evidence, and integrating clinical expertise and patient’s values with the evidence in a way that leads to a rational, acceptable management strategy.

Formal auditing of performance may be needed to show whether the EBM approach is improving patient care.