SDMA

RE: SDMA

Lucy Fleming — Tue, 29 Oct 2019 12:58:14 GMT

[quote user="Anthony Dennison"]some of our vets are recommending perioperative fluids or CKD work up from a one off SDMA value of 16 or 17 [/quote]

I suppose from the point of view of perioperative fluids, having them on IVFT support blood pressure given "unknown" renal health status could be a sensible compromise between doing nothing and cancelling the needed procedure, putting the fear of god into the client, and launching into a full work up...

RE: SDMA

Neil Wheadon — Fri, 25 Oct 2019 12:03:56 GMT

[quote user="Anthony Dennison"]I've been banging my head against all surfaces trying to explain to people it needs to be a paired test.[/quote]

If I remember anything from this thread and in RCVS reflection mode, it will be this very fact.

Neil

RE: SDMA

Beats — Fri, 25 Oct 2019 10:26:27 GMT

[quote user="Anthony Dennison"]We have added SDMA on to our PABs[/quote]

Have you considered being more thorough and doing an iohexol clearance test instead? I'm worried that you're cutting corners and could be missing patients with early CKD / reduced GFR

https://www.rvc.ac.uk/pathology-and-diagnostic-laboratories/therapeutic-drug-monitoring#panel-why-do-the-test

RE: SDMA

Anthony Dennison — Fri, 25 Oct 2019 09:36:07 GMT

I'm glad there is this conversation here. We have added SDMA on to our PABs - some of our vets are recommending perioperative fluids or CKD work up from a one off SDMA value of 16 or 17 (upper reference range is 14). I've been banging my head against all surfaces trying to explain to people it needs to be a paired test.

RE: SDMA

Charlotte Marshall — Tue, 22 Oct 2019 11:42:03 GMT

I have to admit the usefulness of sdma for me was queried when I discovered that royal canin who we use did not advise starting cats with raised sdma on renal diet until they were in iris stage 2.

If we are not going to start them on renal diets earlier then how does it help? The only thing might be checking them more regularly. But if I have an index of suspicion which is why I tested then I would probably be doing that anyway. If it was part of a routine screening program with geriatric clinics then that is going to be done regularly anyway too.

RE: SDMA

Lucy Fleming — Tue, 22 Oct 2019 08:27:43 GMT

[quote user="Neil Wheadon"]I wonder what centres using radioactive Iodine do?[/quote]

My understanding is that they (if possible) treat medically initially to get a better idea of what's going on. If renal disease unmasked I imagine in most cases they would probably still treat. As David says, treating the thyroid disease the priority, and manage the renal disease. If it was very severe/ unstable they might not, I suppose, in case of irreversible hypothyroidism?

RE: SDMA

David Mills — Mon, 21 Oct 2019 21:59:35 GMT

Recent work suggests that treating hyperthyroidism properly should be the priority, sod the renal disease, and leads to a longer life. Tim Williams at RVC has done a bit on this.

Cats with renal disease have renal disease. The hyperthyroidism just masks the numbers.

RE: SDMA

Neil Wheadon — Mon, 21 Oct 2019 21:27:21 GMT

I'm only throwing this one out there but this study talks about SDMA where it shows an ability to detect cats whose subsequent thyroid treatment unmasks renal failure. Yes it has a sensitivity of only 33.3% but would be useful where irreversible treatment is being considered, as it flags cats up before treatment. I wonder what centres using radioactive Iodine do?

https://www.ncbi.nlm.nih.gov/pubmed/29377360

There is a conflict of interest at the end

M. Peterson has received honoraria from IDEXX Laboratories. Ha ho, Iain

Neil

RE: SDMA

Kate Richardson — Mon, 21 Oct 2019 12:56:42 GMT

I don't think SDMA has added much to the party- it is included as standard in the weln idexx profile which I use a lot, but it doesn't add any value in the vast majority of cases. The only ones that it may be helpful in are the ones with low muscle mass as ?Thomas noted, where creatinine may be lower than expected. But a urine SG is FAR more helpful in my opinion. I agree it has probably led to many cats being diagnosed with early kidney disease than may actually have it. As an aside, one of my biggest bug bears with this is the cats who get put onto a renal diet and owners who are then led to believe they MUST eat this and nothing else (even if not enjoying it) and especially the owners who can ill afford the prescription diet, and then can't afford to check the cats blood pressure. Far better to just get the cat eating wet food and spend money on checking its blood pressure and treating it if needed. Hypertension is the most detrimental and potentially devastating effect of renal disease in my experience and it's amazing how few cats get screened for it.

RE: SDMA

David Mills — Sun, 20 Oct 2019 22:57:38 GMT

Iris isn't independent.

There was a thread on here about SDMA a couple of years ago. It isn't specific for renal issues despite IDEXX saying otherwise.

The test may be useful. But I've seen too many misinterpretations of it, meaning cats are denied appropriate therapy or overtreated.

I can't see a place for it really.

RE: SDMA

Neil Wheadon — Sun, 20 Oct 2019 22:48:54 GMT

[quote user="Beats"]How many useful and truly objective papers are there for any diagnostic test?[/quote]

In the case of renal matters we are indeed fortunate to have IRIS.

Digging a little deeper the guidelines are updated for 2019 to include SDMA. Of interest is that you need to confirm it twice

Staging is based initially on fasting blood creatinine or fasting blood SDMA concentration or (preferably) both assessed on at least two occasions in a hydrated, stable patient. The dog or cat is then substaged based on proteinuria and blood pressure.

http://www.iris-kidney.com/pdf/IRIS_Staging_of_CKD_modified_2019.pdf

Neil

RE: SDMA

Beats — Sun, 20 Oct 2019 22:10:15 GMT

[quote user="Iain Richards"]Are there any papers on SDMA that are not sponsored by IDEXX?[/quote]

It would be (highly?) unlikely that there would be, and if there were then it would be likely that instead of commercial-bias, they would either have:

1) Academic bias (e.g. pressure-to-publish / pressure-to-perform)

2) Poor study design or implementation (e.g. lack of funding / self-interest)

How many useful and truly objective papers are there for any diagnostic test?

RE: SDMA

Beats — Sun, 20 Oct 2019 22:05:02 GMT

[quote user="Iain Richards"]The concept of biomarkers is great, but what do we actually understand about what they truly mean. Do all animals with raised SDMA develop renal failure? Do all animals with a raised BNP develop heart failure? ANd don't get me started no raised ALT!![/quote]

Not all patients with a rectal temperature of 39.9'C are truly pyrexic - doesn't stop me taking a rectal temperature.

Not all overweight patients die young - doesn't mean that encouraging weight loss may be sensible.

Not all patients with enlarged lymph nodes die of lymphoma.

Not all patients with a palpable abdominal mass would die as a result of it not being palpated (while some doubtless die as a result of it being palpated).

Often it is suggested that to avoid overdiagnosis and overtreatment it is necessary to stop doing so many blood tests (or measuring so many parameters on a given blood sampling irrespective of the reason) - I would argue that this often becomes a flawed argument for 2 reasons:

1) The extrapolation of this is that of not carrying out "health checks" or at least limiting those seriously (no abdominal palpation, no lymph node palpation, no rectal temperature etc.). Yet the same folk advocating doing less blood tests often say this is based on it not being necessary in the presence of a healthy physical examination; I would say that many/most aspects of a physical examination are therefore not necessary in the presence of a healthy history. [I'm not saying whether I agree with the premise that less "healthy" patient assessment/testing would be a good thing or otherwise]

2) Overdiagnosis / overtreatment is a result of "overinterpretation" of observations / results, not a necessary consequence of it. One can observe a "raised SDMA", "raised BNP", "raised ALT", palpable abdominal mass, mild lymphomegaly, T>39.5'C, anisocoria, cardiac arrhythmia/murmur, skin lump, preputial discharge, dental calculus, saliva-staining of the front paws, enlarged prostate, mild obesity etc. and not do any further diagnostics or therapeutics if you wish. It seems unfair to suggest that 'it wasn't me, the observation made me do it'.

Cost-aside, there is no reasonable argument (to my mind) against including e.g. T4 in every blood sample taken for any reason in a dog or cat. I don't personally consider claiming that it might lead to me overdiagnose and overtreat hypothyroidism in dogs is a valid reason.

Obviously, cost can't be set aside. But in relation to SDMA (or any other parameter), if its testing is part of a package of tests and it is more-efficient / simpler / other-valid-reason to have this package of tests run on every blood sample in a given clinic set-up, then I can't see how that can be a negative.

RE: SDMA

Iain Richards — Sun, 20 Oct 2019 17:29:26 GMT

Are there any papers on SDMA that are not sponsored by IDEXX?

The concept of biomarkers is great, but what do we actually understand about what they truly mean. Do all animals with raised SDMA develop renal failure? Do all animals with a raised BNP develop heart failure? ANd don't get me started no raised ALT!!

RE: SDMA

Francisco Gomez — Thu, 17 Oct 2019 19:03:33 GMT

[quote user="KathW"]

I’ve found it more useful to aid diagnosis ( and ongoing monitoring if owners wish for this or there is a sudden change in clinical condition eg significant weight loss) in cats with a low body condition score (2/9 or 3/9) when creatinine may be mid or lower end of the normal range. When creatinine is raised ( IRIS stage 2 or higher) I don’t it adds anything.

[/quote]

We use SDMA as part of (optional) preGA package and I found this very useful in elderly cats where Crea/urea might be lower for other reasons ie low muscle mass. I don't use it for diet.

Like any other test, the key is interpretation.

[quote user="Julie Innes"]

patronising IDEXX rep, who seemed to be suggesting that the reason I didn't do more SDMA testing was that I was a dinosaur and didn't understand it.....

[/quote]

I'm afraid I rep calling you a dinosaur is a rep not being very good at explaining benefits and becoming frustrated (a bit disappointing to have IDEXX send you someone like that), not a test problem.

RE: SDMA

Clive Ansell — Thu, 17 Oct 2019 18:35:35 GMT

[quote user="Evelyn Barbour-Hill"]

[quote user="niamhjl"]that dogs will live 2.5 times longer on renal diet than not, and cats will live 3 times longer.[/quote]

[/quote]

Amazing, we are going to see cats and dogs living into their 40’s and 50’s

RE: SDMA

Neil Wheadon — Thu, 17 Oct 2019 16:27:25 GMT

Short communication on the IRIS website. Written in 2016 and the paper has Elanco written on it

Glomerular filtration rate is the thing we need to measure

Now the quote

At present, the available data suggest that plasma (or serum) concentration of SDMA reflects GFR in cats and dogs, may be more sensitive than blood creatinine for early detection of CKD, and is less affected by loss of lean body mass than blood creatinine. Clearly SDMA has utility for the diagnosis and management of dogs and cats with renal disease.

Now of interest is (applies to cats)

A persistent increase in SDMA above 14 μg/dl suggests reduced renal function and may be a
reason to consider a dog or cat with creatinine values <1.4 or <1.6 mg/dl, respectively, as
IRIS CKD Stage 1.

One word for me sticks out PERSISTENT, so should we be resampling these and not relying on one blood result?

Neil

RE: SDMA

Evelyn Barbour-Hill — Thu, 17 Oct 2019 14:50:04 GMT

[quote user="niamhjl"]that dogs will live 2.5 times longer on renal diet than not, and cats will live 3 times longer.[/quote]

RE: SDMA

niamhjl — Thu, 17 Oct 2019 14:37:13 GMT

We were taught on my BSAVA medicine certificate by Penny Watson, that dogs will live 2.5 times longer on renal diet than not, and cats will live 3 times longer. There obviously was a reference for this in the notes but I don’t have it to hand. This was before SDMA came out though so no idea if starting earlier would make a further difference.

RE: SDMA

Thomas Johnson — Thu, 17 Oct 2019 11:11:20 GMT

[quote user="Neil Wheadon"]My impression with SDMA is that the train will hit the buffers and explode at some stage. There are various warning signs along the way and at the moment we have one 200 metres out saying slow down, which means diet, phosphate binders etc. The question with SDMA is that it provides a warning sign 400 metres away. The question is, will anything at that stage slow the train down. IDEXX and Hills say yes and intuitively you think it will, but will it?[/quote]

What I don't know is the impact on survival time of the various differences between renal diets and normal diets. Do the diets slow the rate of loss of tubular function, or do they allow the cat to cope with the loss of tubular function for longer? If the former then getting them on to the diet sooner rather than later would seem sensible, if the latter then you can probably wait until phosphate levels start to increase before changing. The other consideration might be that diet change is often easier before the cat is showing clinical signs of renal disease as their appetite is often affected.

RE: SDMA

Neil Wheadon — Thu, 17 Oct 2019 10:49:11 GMT

My impression with SDMA is that the train will hit the buffers and explode at some stage. There are various warning signs along the way and at the moment we have one 200 metres out saying slow down, which means diet, phosphate binders etc. The question with SDMA is that it provides a warning sign 400 metres away. The question is, will anything at that stage slow the train down. IDEXX and Hills say yes and intuitively you think it will, but will it?

Neil

RE: SDMA

KathW — Thu, 17 Oct 2019 09:49:11 GMT

RE: SDMA

Julie Innes — Thu, 17 Oct 2019 08:58:13 GMT

I'm glad this discussion has been raised, as I had a bit of an argument with a very patronising IDEXX rep, who seemed to be suggesting that the reason I didn't do more SDMA testing was that I was a dinosaur and didn't understand it.....

maybe we need something like the EPIC study, to prove one way or another whether early diagnosis and dietary adaptation will actually make a difference to outcome/ survival time. Or if the incidence is so great, maybe we should just put all cats onto renal diet at a certain age and skip the middle man. Have to admit, I am a bit sceptical about the usefulness of SDMA in every case (as they would like us to use it!) Glad it's not maybe not just me being a dinosaur!

RE: SDMA

Sarah Keir — Wed, 16 Oct 2019 09:21:54 GMT

The papers I have read regarding SDMA use it as a surrogate outcome. As far as I know there is no proven link between early management of early kidney disease and improved quality of life or delaying progression. Without the research that shows one leads to the other, what are we actually doing?

RE: SDMA

Kate Richardson — Tue, 15 Oct 2019 21:42:43 GMT

I expect they suggested a renal diet not that I’m the slightest bit cynical