This is an area that I thought was fairly straightforward but the more I look into it the more confused I become.
There are all these different ways of assessing the severity of inflammatory arthritis including PsARC for PsA and DAS which is primarily for RA. Or at least I thought that the use of DAS / DAS28 was restricted to RA …
In the UK at least, these different systems come into their own when assessing whether biologics are on the cards. For example NICE, the organisation which determines the rules and guidelines concerning drugs, stipulates (or possibly just ‘recommends’) that PsARC should be used 12 weeks after starting a biologic to measure whether the response is good enough to stay on the drug. And because a baseline is required, the advice is to use PsARC to assess the severity of PsA before commencing biologic therapy.
Any of you who fancy practising a bit of home rheumatology might be interested in this poster which shows the joints tested for PsARC plus how to do it:
https://www.psoriatic-arthritis.co.uk/Assets/Files/Content/Rebranded_Content_/Rheum_Poster.pdf
Recently I’ve heard of people with PsA in the UK and elsewhere being assessed using the DAS system. It looks like the British Society for Rheumatology do not think that this is best practice, at least not in measuring response to biologics. This is an excerpt from their ‘2012 Guidelines for the treatment of Psoriatic Arthritis with biologics' entitled 'Outcome Measures':
'As stated above, the PsARC is the current recommendation for response assessment in peripheral arthritis. The ACR response criteria have also been shown to be discriminative in polyarticular PsA , but are generally too cumbersome and time consuming for routine clinical practice. Other composite arthritis measures have been validated in PsA. The EULAR responses, based on the DAS and DAS28 scores have been shown to be responsive in polyarticular disease but there are numerous concerns about their use in the general PsA population (i.e. lack of validity in oligoarticular disease or those with predominant lower limb involvement, remission cut off validated in RA but not in PsA , global disease activity may be influenced by other aspects of psoriatic disease [such as enthesitis, psoriasis, axial disease], PsA patients show a less linear relationship between disease activity and acute phase response).'
In other words, if DAS is applied to you, your feet might get missed off, you might falsely be declared to be in remission and specifically PsA things like enthesitis may not be taken into account. Anyone who can translate the last sentence has my respect.
Here's a link to the full article:
www.rheumatology.org.uk/inc...
This is a bit of a nerdy post I suppose but I’m sure most of us are interested in just how our rheumatologists assess our disease activity / severity. And sometimes we’re just plain mystified. As the poster shows, the main emphasis is on joint swelling and tenderness though there is some wriggle room where access to biologics is concerned in the ‘global assessments’ which could cover just about anything.
How does your rheumatologist assess your disease? In particular, do they consider pretty much all your joints? Or just the DAS ones which, notoriously, exclude the feet? And do they tell you what their method is even if they don't actually use the name of it?