Professor Moore about drugs for neuropathic pain
On the international congress of neuropathic pain (NeuPsych) 2010 in Athens, professor Moore (University of Oxford, UK) put a cold and fishy eye on what is really known about the efficacy of drugs in neuropathic pain.
In his talk he pointed out:
- “The great thing about being right is that you don’t have to change your mind so often.”
And Moore cited in the beginning of his talk Ioannides:
- “The trouble with evidence based medicine I that most of it is wrong.” (Ioannides PLOS medicine 2005 “Most published research findings are false.”)
Clinical relevant and significant is not always a desirable state
He pointed out that increasingly attention is turning to what constitutes a clinically useful outcome. And defines such an outcome as an outcome that is important for the patient. Not just one that is measurable.
Clinical trial outcomes indicates that not every patiënt benefits from a particular treatment. And that in many painful conditions most do not benefit enough.
What the patiënt perceives as relevant is not always comparable to what has been measured during clinical trials. But if we succeed in treating pain, those patients whose pain is reduced significantly also benefit in a range of other ways. With improved sleep, less depression, and improved quality of life. Good pain treatment therefore is the key.
‘What is a significant pain benefit?’
From the clinical trial perspective a moderate effect can be defined as 30% reduction in pain. And a substantial effect can be defined as more than 50% reduction from baseline scores. Patients when asked what they perceive as relevant see this differently. A satisfactory reduction of pain is a reduction of pain under 3 points on the 11 point numerical rating scale (NRS).
Thus, he showed that clinical relevant reductions of 50%, as defined by trial architects, does not necessarily be in line with what a patiënt perceives as a clinical meaningful reduction. That is a NRS of 3 or less.
Score 8, after therapy 4
Professor Moore then demonstrated this using a graphic (below). Patients who score at baseline an 8 and after therapy 4, being a clinical relevant change according to the protocol, it would not be such a change for the patient. Who desires to reach a state of pain defined as less than 3 on the NRS.
According to the protocol such a patiënt is a responder. But at the same time the patiënt did not reach the desired state of score less than 3.
On the other hand, a patiënt starting with 3,5 and ending on 2,5, is according to the protocol a non-responder, although this pain score reaches a desired state.
A. Moore DRUG TREATMENTS FOR NPPs – LOOKING AT THE EVIDENCE WITH A COLD AND FISHY EYE European Journal of Pain Supplements, Volume 4, Issue 1, May 2010, Page 46
Prof. dr. J.M. Keppel Hesselink
‘Professor Moore about drugs for neuropathic pain’
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