EVIDENCE BASED 2002

SUMMARY: Evidence Based Medicine  (EBM) is still in its infancy. Applying medical research evidence in clinical practice remains problematic.  Randomised Controlled Trials (RCT) have limited relevance to management of the individual patient.  The high annual volume of published clinical research means that clinicians and litigators must depend on a variety of digests. 

Many litigators hoped Evidence Based Medicine (EBM) would resolve conflicts about Causation and, by way of EBM-derived Clinical Practice Guidelines (CPG), clarify Standard of Care. 

EBM is “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients” ¹.

The first decade of Evidence Based Medicine has been characterised by vigorous debate between the evangelists and the sceptics about its relevance to clinical practice. 

Applying medical research evidence in clinical practice remains problematic. 

Even its champions acknowledge that EBM is simply a tool, and that skillful doctors also use individual clinical expertise¹.

The main types of clinical research evidence in increasing order of reliability ² - and decreasing order of abundance -  are case reports, case series, case-control studies, cohort studies, systematic reviews and meta-analyses. 

Randomised Controlled Trials

The gold standard for the effectiveness of a given medication or therapeutic intervention is the RCT: patients are allocated randomly to a therapy or mock therapy (placebo), and neither patient nor assessor knows to which. 

In theory, ineffective therapies, that might be dangerous and/or expensive, can thereby be withdrawn from standard medical care. 

In practice, applying RCTs to clinical practice is far from straightforward³.  Randomised Controlled Trials have limited applicability for a variety of reasons. 

Studies are unrepresentative

Common patient exclusions for medication research purposes include age >64, pregnant, women of child-bearing age, those with mixed diagnoses or co-morbidity, drop-outs, and patients who show lack of cooperation. 

That is, those who are selected for clinical trials are not typical of the population being treated^4,5. 

Conclusions drawn only from the drug trials that are published may be biased^6,7.  Research that produces “negative” results frequently remains unpublished and this important information is therefore excluded from meta-analysis. 

Further, most journals have not yet implemented the CONSORT recommendation¹⁵ that results of a RCT be discussed in context of all the available evidence⁸.

Shortage of scientific evidence for traditional therapies

There is little or no empirical evidence for the effectiveness of most passive physiotherapy in accelerating healing.  What is perhaps more alarming to lawyers as counsel (and as potential patients) is that the same generalisation can be made about the majority of traditional medical treatments.

The very fact that many therapies are hallowed by time often makes it difficult to design therapy trials that are ethical. 

Furthermore, patients, and sometimes assessors, cannot be “blinded” to therapies in that it is self-evident whether the intervention is real or mock. 

Difficulties in applying evidence to the care of individual patients

There is a wealth of biological variation between individual patients/clients, including those who have suffered a particular injury or illness. 

More important perhaps, clinical research attempts to answer questions with more certainty by excluding as experimental subjects those patients who have additional medical conditions that might complicate the pathology being studied. 

The reality is that most claimants and plaintiffs do have co-morbidity, and different medical conditions do interact with each other. 

Cook-book medicine

Threats to curtail clinical freedom cause some physicians to bristle.  Indeed, the idiosyncratic application of unorthodox therapies has frequently triggered major medical breakthroughs. 

Nevertheless, the movement to eliminate useless treatments that are useless, expensive and potentially dangerous long preceded this first decade of Evidence Based Medicine. 

Hierarchy of Evidence

The proliferation of medical knowledge is so great that the standard cross-examination question, “What journals do you read regularly” is unrealistic for assessing a medical expert’s professional updating. 

A British study⁹ found that general internists would need to review 19 articles per day, every day of the year, to keep up with all the medical advances reported in the primary journals. 

In reality, British medical consultants spent an average of less than an hour a week reading the  clinical research literature in their field of practice. 

Counsel should be aware that review articles of the following types are more appropriate sources of EBM, in descending order of desirability^10,11: