Saturday, 11 February 2023

Systematic review of CLIPPERS studies


Wind-battered trees on Brean Down

One of the difficulties in studying conditions like CLIPPERS is their rarity meaning that there are comparatively few cases to draw from. CLIPPERS, with it's variability of symptoms and outcomes and difficulties in concrete diagnosis has additional challenges. However, now that there have been over ten years of scientific publications on CLIPPERS there are opportunities to get a better overview by combining together earlier work. Dr Al-Chalabi and colleagues from the University of Toeldo published a paper in 2022  titled "Clinical characteristics, management, and outcomes of CLIPPERS: A comprehensive systematic review of 140 patients from 100 studies" to try and achieve this. A systematic review is where a collection of previous works are combined following a protocol which strives to ensure quality and minimize bias to hopefully come to stronger conclusions than might be possible looking at the individual studies. In the case of this review, the "clinical characteristics, treatment strategies and outcomes" of CLIPPERS were assessed.

My reading of the review is that the authors drew together some common themes from the individual studies but that the amount of variability and uncertainty still hindered their ability to draw firm conclusions, even in over 100 nominal CLIPPERS patients. They found 60% of their cohort were male and the mean age of onset was 46 years (which is very close to the age I first got symptoms). The most common (but not the only) symptoms, in order, were ataxia , diplopia, and dysarthria; my own experience was diplopia first, then quite quickly followed by ataxia, and latterly by some dysarthria just as I began treatment. They also found that around 15% of the patients studies had some form of malignancy which presumably means CLIPPERS wasn't their ultimate diagnosis (but I am not a doctor). In terms of long-term treatment, Azathioprine and Methotrexate, were the most common, but not the only, drugs. 

The authors also report that a shorter time on steroids was associated with an increased risk of CLIPPERS relapse which, to me, is the most interesting of their conclusions, possibly, and very unscientifically and with no evidence, because I have long had a gut feeling that longer steroid tapers might be better. The authors suggest that, going forward, steroid tapers should be very slow, although they don't state what "slow" means - presumably months?

These studies are important and as well as making the most of previous studies can hopefully direct future research.

Read other articles in this series at Living With CLIPPERS.

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Living With CLIPPERS by Bill Crum is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.