Wednesday, 28 May 2014

A complex problem

In an earlier post I described what makes a review 'systematic'. In considering all the relevant research, we have to use transparent and replicable methods. Ideally, a reader of our review should be able to reproduce the review and get the same results. An important part of our methods is to clearly specify the nature of the research to be included in the review, our ‘inclusion criteria’.

Inclusion criteria are set out using an acronym called PICOS which stands for Participants, Interventions, Comparators, Outcomes and Study designs. In a review looking at a new drug to improve survival in breast cancer, for example, the participants are those with breast cancer, the intervention is the new drug, the comparator the currently prescribed drug, the outcome survival and usually the study design will be randomised controlled trials (often abbreviated to RCTs) as these are the most rigorous form of medical research.

Rarely, however are systematic reviews so straightforward.  The OKIS review is particularly complex as our inclusion criteria are very broad.  The participants are people with neuromuscular disorders of which there are many types. Neuromuscular disorders can involve the structure of the muscle cells in conditions such as Muscular Dystrophy the neuromuscular junction where the nerves and muscles meet such as Myasthenia Gravis and the motor nerves in the arms, legs, neck and face as in Charcot-Marie Tooth Disease to give just a few examples. This review also includes neuromuscular disorders arising from central nervous system causes such as Stroke, Multiple Sclerosis and Post-Polio Syndrome. The common element in all these disorders for this review is knee instability.

Another complexity in this review is that there is more than one type of orthotic intervention that may be used to help with knee instability. Some orthoses are fixed below the knee supporting the ankle and foot. Others are longer and cover the knee, ankle and foot. For severe weakness they can also include a hip band. Each one has its own acronym! The range of possible comparators is equally diverse. And, you’ve guessed it, the range of outcomes is wide and varies according to the conditions investigated. Pain, walking ability, usage of the orthotic and patient satisfaction are just some of the outcomes of interest. Furthermore, this topic area is at an early stage of research so we cannot restrict our study design inclusion criteria to RCTs as these have not been conducted in great numbers. We will, therefore, consider a range of study designs.

The complexity of this topic will be challenging at every stage but we now know the terms we need to use as we start to search for all the relevant research...but that will have to be the subject of another blog post!

Blogger: Debra Fayter

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