Statins are famous, and their fame lies in their ability to bust cholesterol, the villain in many medical disorders such as heart attack (myocardial infarction) and stroke. Some may add that statins are infamous, and this is partly because of their side effects such as muscle pain. Love them or hate them, we can’t get away from statins…even as the debate rages about their benefits and downsides.
It is not surprising therefore that the statin debate will filter into neurology. The sticking point here however has nothing to do with cholesterol busting, but all to do with whether statins increase or reduce the risk of developing Parkinson’s disease (PD). Strange as it may seem, statins and PD have a long history. And a positive one generally, I hasten to add. There is a large body of evidence to suggest a protective effect of statins on PD as reflected in the following studies:
The authors of this paper set out to investigate ‘the controversy surrounding the role of statins in Parkinson’s disease’. In this retrospective analysis of over 2,000 people with PD, and a similar number of control subjects, theauthors found that statins significantly increased the risk of developing PD. This is clearly a conclusion looking for a fight!
I must admit I was totally unaware there was any controversy about statins and PD. I was therefore curious to find out what studies are out there fuelling it. Which other trials have bucked the trend and reported an increased risk of PD from statins? And where best to find the answers but in PubMed, the repository of all human knowledge! And I found that there were only a few studies that did not report a protective effect of statins on PD, and these studies concluded, quite reasonably, that they found no relationship between PD and statins. Here are a few of the studies:
These papers reporting the absence of evidence seem happy to engage in an amicable debate to resolve the question.
One study however stood out like a sore thumb because it positively reported a negative effect of statins on PD (try and work that out!). This 2015 study, also published in Movement Disorders, is titled Statins,plasmacholesterol, and risk of Parkinson’s disease: a prospective study. The paper concludes that “statin use may be associated with a higher PD risk, whereas higher total cholesterol may be associated with lower risk“. Not only are the authors arguing that statins are bad for PD, they are also suggesting that cholesterol is good! This is a paper that was itching for fisticuffs.
What is a jobbing neurologist to do? What are the millions of people on statins to do? Whilst awaiting further studies, I will say stay put. Go with the bulk of the evidence! And keep track of TheSimvastatin Trial, funded by TheCure Parkinson’s Trust. This trial is looking at the benefit of statins in slowing down PD. And surely, very soon, the science will lead to a resolution of the argument-all you need to do is keep track of everything PD in Neurochecklists.
Many people with difficult to control migraine however really have just that…difficult to control migraine. And it is the most avid neurologist who doesn’t silently sigh and grunt at referrals which say the patient has tried every migraine treatment, to no avail. And with good reason: the journey for people with chronic migraine is hardly ever smooth-sailing.
Why does migraine remain such a pain, and what hope is there to relieve the headache for patients and their neurologists? Here are 8 prospective candidates jostling to soothe the pain.
2. Migraine with cranial autonomic symptoms-clarified
Migraine with unilateral cranial autonomic symptomsis a new construct for most jobbing neurologists (OK I may just be speaking for myself here). Unilateral cranial autonomic symptoms (UAS) refer to one-sided symptoms such as reddening of the eye, blockage or running of the nose, a droopy eyelid, and a small pupil. These features are however classically seen in conditions called trigeminal autonomic cephalalgias (TACS), the main one being cluster headache.
Neurologists often see people with classical migraine but who, in addition, have UAS. The cognitive dissonance this causes the neurologist is relieved by making a diagnosis of cluster migraine. It is therefore important to know that unilateral cranial autonomic symptoms are common in migraine. The authors studied >750 migraine sufferers who also had UAS, and report that it is a severe, one-sided headache. Worse still, it goes on for more than the 72 hours which headache experts have ‘specified’ as the maximum duration for migraine. Naughty, naughty. Hopefully this study will put the final nail in the coffin of cluster migraine-it is Migraine with UAS from now on.
Neurologists have a long list of interventions for migraine. The treatments range from Triptans to Topiramate, from Propranolol to Pizotifen. But the long list of interventions is no comfort for the equally long list of dissatisfied chronic migraine sufferers. Perhaps what we need are newer and better drugs. And monoclonal antibodies are in the frontline here. Take TEV-48125and AMG 334 both reported in Lancet Neurology. These are monoclonal antibodies against the calcitonin gene receptor peptide (CGRP) receptor. The articles are classical illustrations of bench-to-bedside neurology, treatment following where the hypothesis leads. The hypothesis in this case stipulates that the CGRP system is central to the pathology in migraine, and CGRP may be a migraine biomarker. TEV-48125 and AMG 334 are entering phase 3 trial stages. And we can’t wait, what with both treatments having a unique 4-weekly subcutaneous injection regime! AMG 334, also known as erenumab, has passed phase 3 trials with good results.
5. Statins and Vitamin D: new tricks for old dogs
Statins are very old dogs in medicine, and their classical trick is to lower cholesterol levels. They are however very adaptive, these statins. They have edged into secondary stroke prevention, and they are now trying to muscle into migraine prevention. But for migraine they are planning a double act with Vitamin D. The cat was let out of the bag by Annals of Neurology in an article titled Simvastatin and vitamin D for migraine prevention: A randomized, controlled trial. There were only 57 study subjects but the results are encouraging; >25% of the study subjects reported a >50% reduction in migraine days; only 3% of those not on the magic combination showed this type of improvement. Note here that neurologists never promise you 100% reduction in your migraine days. Clever, clever.
6. Memantine-another old dog
Another old dog looking for new tricks is Memantine. This is a drug which usually gets its accolades in the fields of dementia and eye movement disorders. It is however not getting the appreciation it thinks it rightly deserves, and it is seeking a wider audience. And is there a wider audience than in the migraine arena? Memantine made its grand migraine debut through the journal Headache in an article titled Memantine for Prophylactic Treatment of Migraine Without Aura. It may turn out to be a damp squid because the researchers only compared it to placebo. But guess its unique selling point… its potential safety in pregnancy. We have to wait and see what the migraine arena masters think of this.
7. Transcranial magnetic stimulation (TMS):old tricks for a new dog
Uncertainty and doubt abound in Neurology. There are many evidence-free areas where experts rub each other the wrong way. These controversies are big and occur in all neurology subspecialties. Controversy-busters have tried for about a decade to iron out these wrinkles on neurology’s face, but the unanswered questions remain. This is why there is a 10th World Congress of Controversies in Neurology (CONy) holding in Lisbon this year.
I want to assure you I have no conflict of interest to declare in this blog. My interest is to explore which questions have plagued this conference over the last 10 years to pick out the most controversial topics in neurology. To do this I reviewed all previous conference programs and focused on the items that were slated for debate. I looked for practical topics that have remained unresolved, or are just emerging. Here are my top controversial neurological questions:
Which should be the first-line therapy for CIDP? Steroids vs. IVIg
Should disease-modifying treatment be changed if only imaging findings worsen in multiple sclerosis?
Should disease-modifying therapies be stopped when secondary progressive MS develops?
Should non-convulsive status epilepsy be treated aggressively?
Does traumatic chronic encephalopathy (CTE) exist?
Does corticobasal degeneration (CBD) exist as a clinico-pathological entity?
Is ß-amyloid still a relevant target in AD therapy?
Will electrical stimulation replace medications for the treatment of cluster headache?
Carotid dissection: Should anticoagulants be used?
Is the ABCD2 grading useful for clinical management of TIA patients?
Do COMT inhibitors have a future in treatment of Parkinson’s disease?
Going through this list, I feel reassured that the experts differ in their answers to these questions? The acknowledgement of uncertainty allows us novices to avoid searching for non-existent black and white answers. It is however also unsettling that I thought some of these questions had been settled long ago. It goes to show that apparently established assumptions are not unshakable?
Do you have the definitive answers to resolve these controversies? Are there important controversies that are missing here? Please leave a comment
Three recent articles caught my interest because they point to potential new roles for old drugs.
The first paper in the Lancet Neurology suggests a role for Riluzole in hereditary cerebellar ataxia. With 50% of the treatment arm improving against 11% of the placebo arm, I hope this is not false hope for patients with Friedreich’s ataxia (FA) and spinocerebellar ataxia (SCA).