Evidence Based Medicine

[hhh]

One thing I have not heard or read you debate about is evidence based medicine. This has evovled over the last 5 years particularly, with management guidelines coming out all too frequently. A good example is the journal Spine which would almost soley publish surgical papers. Now that surgical procedures aren't recommended in EBM, there has been a distinct shift to not include such papers.

I would like to know your thoughts and attitiudes on EBM, with a particular emphasis of sports medicine. The difficulty with sports medicine compared to other areas of medicine is that there is scanty research (apart from a few of the major injuries such as achilles tendonosis), and that which does exist is not of the highest standards (ie large subject RCT's). How many sports injury meta-analysis have you seen? I know a big aspect of sports medicine is anecdotal evidence but do sports medicine professionals risk losing credability if they don't keep up with trends in general medicine? As Bogduk has been quoted: "In God we trust, all others bring data". Whilst sports doctors are already under-recognised in their field, could this potentially provide a reason for the lack of recognition? Elite sport, particularly in the USA and UK has tremendous amounts of money, why isn't quality research more supported by the sporting community?

[injuryupdate]

EBM should all be about Levels of Evidence, with your classic 1a = meta-analysis of all RCTs down to 4 = expert opinion.

The problem is that we don't have enough sub-definitions of category 4. Expert opinion from large numbers of experts held over a number of years with good theoretical basis is often very likely to be true, but it is classed as no 'better' than a fad which has a few experts on the bandwagon.

EBM and Cochrane reviews can fail in areas where RCTs are unlikely to get performed. For example, in 2000 there was a Cochrane review done to suggest that there was NO evidence that any treatment worked for Achilles tendinopathy. There have been some decent trials since then, but to suggest that no one had any idea how to treat this condition in the year 2000 is wrong, it merely indicates an obsession with RCTs = the only form of evidence.

A good recent letter from the BMJ suggested that the Vioxx fiasco lasted longer than it should have because they took the slow option of investigating the cardiotoxicity of Vioxx with an RCT rather than quicker options like case control studies, which are less trendy:

http://www.injuryupdate.com.au/forum/showthread.php?t=446

Whilst we want sports medicine to have more trials performed, the real drivers for trials are Pharmaceutical companies (and they introduce their own bias). Drug companies can manipulate market share by selectively publishing trial results. Surgeons (and most clinicians) don't have the motivation to perform trials as they are too busy with patients and can't increase their own market share above being booked out.

Governments are probably in the best position to order trials to test what they are spending their money on.

Currently governments (except for NZ) don't know how much money they are spending on sports injuries. I think the big EBM step in sports medicine is national sports injury surveillance. Then if things are getting done differently in different parts of the country you might get a clue from the national data whether things should be tested.

For example, given how many hydrodilatations are performed in Melbourne, either they are going to get better shoulder outcome stats than the rest of the country (in which case this procedure should be exported) or they are not (in which case maybe the funding for the procedure should be lowered or withdrawn). Looking at national outcome patterns (if you can get them on file) would give you much bigger numbers (and therefore maybe more clues) than RCTs of small numbers.

[sydunisportsmed]

From the editorial in this month's AJSM, this is the list of study types they will publish (contributors must categorise by study type according to this list):

Meta-analysis: A systematic overview of studies that pools results of 2 or more studies to obtain an overall answer to a question or interest. It summarizes quantitatively the evidence regarding a treatment, procedure, or association.

Systematic Review: An article that examines published material on a clearly described subject in a systematic way. There must be a description of how the evidence on this topic was tracked down, from what sources, and with what inclusion and exclusion criteria. The AJSM will consider such articles for its "Current Concepts" section.

Randomized Controlled Clinical Trial: A group of patients is randomized into an experimental group and a control group. These groups are followed up for the variables/outcomes of interest. A nonrandomized controlled clinical trial is considered either a cohort study or a case series, depending on how successfully the experimental and control groups are matched.

Crossover Study Design: The administration of 2 or more experimental therapies, one after the other, in a specified or random order to the same group of patients.

Cohort Study: Involves identification of 2 groups (cohorts) of patients, one group that receives the exposure of interest and another group that does not, and following these cohorts forward for the outcome of interest.

Case Control Study: A study that involves identifying patients who have the outcome of interest (eg, cases of lung cancer) and patients without the same outcome (controls), and looking back to see if they had the exposure of interest (eg, cigarette smoking).

Cross-sectional Study: The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.

Case Series: Describes characteristics of a group of patients with a particular condition or who have undergone a particular treatment. No control group is used in the study, although the discussion may compare the results to others published in the literature.

Case Report: Similar to the case series, except that only one or a small group of cases is reported.

Controlled Laboratory Study: An in vitro or in vivo investigation in which one group receiving an experimental treatment is compared to one or more groups receiving no treatment or an alternate treatment.

Descriptive Laboratory Study: An in vivo or in vitro study that describes characteristics such as the anatomy, physiology, or kinesiology of a broad range of specimens or subjects or of a specific group of interest.

[sydunisportsmed]

Link for levels of evidence:

http://www.cebm.net/levels_of_evidence.asp