I'm wondering if anybody is aware of studies that have shown measurable benefits from following the National Dysphagia Diets? Things like patients following a recommended level of the NDD had 60% fewer cases of pneumonia than a control group not following the diet. That sort of thing.

I'm trying to weigh risks, costs, and benefits and I'd really appreciate hearing about some well controlled studies.

I have not seen anything on the diets. I have seen research comparing the types of thickeners with different liquids.

You might check the website of the Dysphagia Journal. See:
http://www.springerlink.com/content/0179-051X

You can do a search there of what you are looking for.

Thanks for that site, Robin. I found two articles that might be of interest but each cost $35, and I decided to pass.

I did some other google searching and found several articles of interest. The concensus of what I read was that more studies are needed. I couldn't find any evidence of the degree of benefit, if any, from the various diets.

There isn't even agreement on what foods belong in the various diet levels, which was evident by looking at several different online sources and comparing it to what we were given. Standardizing the diet recommendations is written about by various groups.

While the use of thickened liquids in nursing homes is very widespread, there seems to be a conspicuous absence of outcome-based studies regarding that practice. There seems to be a lot of CYA in nursing home decisions in this regard.

Seeing a swallowing test, it seems "intuitive" that changing the diet will reduce aspiration of food. But I'm having a hard time uncovering evidence that supports that intuition.

Often you can get all you need from the abstracts of the article. If the journal's website doesn't have the abstracts, try PubMed (pubmed.gov).

During a MBSS, there's no need to intuit. You can SEE for yourself whether thickening prevents aspiration....at least during the one-hour the test is taking place.

Yes, Robin, often you can get what you need from the extract. Not in this case, which may well mean that it isn't in the full article either.

You can see in the swallow study which substances are less likely to cause aspiration. Although if you don't see any aspiration, or the aspiration occurs at a thicker liquid and not at the thinnest, you do not really SEE direct evidence. You can get an intuitive feel which are safer. But what happens in a half-an-hour period isn't much proof of anything. I'd like to see evidence, based on many studies. I'm not having much like finding it. I've stopped looking.

Dr. Boeve says, "outcome studies are scant" in this area. Coy's geriatrician says there are no outcome based studies. We see the SLP this morning and I'll ask her the same question.

I couldn't find any long-term-outcome-based studies, either, in a quick pubmed search. (I did find some related studies but nothing that directly answered the question.) At least there do not appear to be any peer-reviewed, randomized clinical trials. There are some short-term randomized trials with swallow-based measures as outcomes, but nothing with longer-term clinical endpoints like pneumonia. I was trying to think how I would run such a study and concluded that it would be pretty tough to do. You'd need a large sample size to detect any difference in pneumonia incidence, but managing the intervention in a large-scale multi-site study would be extremely tough in this population. And there would be all sorts of potential problems with bias, because you couldn't mask the intervention from the caregivers. So it's not surprising that the topic has not really been studied much.

Laurel

Well, I guess it is unanamous then. Dr. Boeve, Coy's geriatrician, Robin, Laurel, and the SLP all cannot find/are not aware of studies relating the incidence of pneumonia to compliance with dysphagia diets.

Depending on where you look, we swallow somewhere between 600 and 2400 times a day. (Just based on counting my own swallows, the higher numbers seem more believable, but I don't know what happens during sleep.)

Every one of those swallows is an opportunity to aspirate bacteria. If you eliminate the risk during eating and drinking, how much does that reduce the total risk? But of course a diet does not eliminate the risk -- it only decreases it by some unknown percent.

So I guess we can say "following a dysphagia diet probably reduces the risk of getting aspirational pneumonia, but we don't know how much."

Interesting.