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Accuracy of DEXA Scans

Posted by njhornung @normahorn, Mar 9, 2024

I am guessing that I am not the only one facing a medication decision based on one DEXA scan with no fractures. That raises the question as to how much reliance we should put on that single measurement. I trust that sites calibrate the instruments according to the manufacturer's specifications. But we read about the importance of proper positioning. I was only asked to lie on a table with no special consideration of position. Does improper position make bones appear denser or less dense? Or is the effect minimal?

Remember the old weight charts that had ideal weight ranges by height and bone structure? Does DEXA factor in bone structure when calculating density. Obviously, there is less bone for the x-rays to penetrate for a fine-boned person than for a heavy-boned one. That could be interpreted has having less bone mineral density which may not be the case.

Any insight or other pertinent questions?

Interested in more discussions like this? Go to the Osteoporosis & Bone Health Support Group.

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rjd | @rjd | Mar 13 8:09am
In reply to @cat1203 "@rjd And you can't rely on the subject/title lines. You start reading a thread that goes..." + (show)
Profile picture for cat1203 @cat1203

@rjd And you can't rely on the subject/title lines. You start reading a thread that goes off the rails with people introducing new topics that have nothing to do with the original post you were interested in and wanted to follow. I wish the admins/moderators would take such posts and put them into an appropriately titled new post.

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@cat1203 Your suggestion is great. I add my vote to a more active organizational role of new postings by the admins/moderators if that is at all possible. It would increase immensely the value of this forum.

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mcallister1002 | @mcallister1002 | 3 hours ago
In reply to @rola "(@normahorn) I'm at the exact same place as you Norma. I had 2 scans, one in..." + (show)
Profile picture for rola @rola

(@normahorn)

I'm at the exact same place as you Norma. I had 2 scans, one in Dec 2022 without TBS VFA(Vertebral Fracture Assessment) & my most recent, Feb of 24, with TBS/VFA.
Second scan performed in a different facility. It's, in my mind, not that I doubt there's a system in place that qualifies the need, but is that system accurate? The list of variables is endless and not cemented unless you've already fractured! Variables such as in machines, positions, technicians, health history, contridicting studies, new data, on and on! I keep reading, watching videos & there's not enough time in the day. Sooner or later it affects your well-being & you need to decide. I've vacillated for over a year. I see my Rheum in April and will make that decision then. Stressed since diagnosis 2022!

Information chgs in time, I get it, but I think the *summary below is still worth noting (could not access articles) and the *article on the stats gathered for use of meds according to "their" research. It is, no doubt, what we ourselves feel most at peace with. Yet, one thing for sure, "Harms from overdiagnosis—Being labelled as at risk of fracture imposes a psychological burden.!" Since we live longer are these the necessary tools, if all else failed, and at the same time I read hip fractures in Finland have leveled off, why? What I am positive about, is mindfulness, practice to incorporate the whole body approach to this dilema.

Osteoporosis: How effective are the medications used to prevent bone fractures? - InformedHealth.org - NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK532851/
https://www.bmj.com/content/350/bmj.h2088
https://www.sciencedirect.com/science/article/abs/pii/S0167494318300694
Recent DXA VFA, you'll have to click to enlarge and swipe to right for added rept.

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@rola I agree with everything you said. I have been keeping up with everything bones, books, videos, reading articles , taking supplements, lifting weights, and worrying about my bones. I have seen my DEXA scores steadily decrease every bone scan. Nothing
I’m doing has stopped my bone loss, so I have decided to stop resisting and go on the bone meds.

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mcallister1002 | @mcallister1002 | 2 hours ago
In reply to @awfultruth "I think we would all want the DXA test to be very accurate with no complicating..." + (show)
Profile picture for awfultruth @awfultruth

I think we would all want the DXA test to be very accurate with no complicating factors, at least before we've had the test. Once we've had the test and if we have a bad score we want complicating factors to explain away that bad score so that we can have some hope that we really don't have that bone loss or that maybe it isn't as bad as it seems. At least it was that way for myself.
I paid to have Lani Simpson review my scans because I had lost so much bone between 2 of the scans. Unfortunately she said the scans were good and my bone density was dropping rapidly. At least I knew for sure or as close to sure as I was going to get that I was declining in bone density and that my efforts so far have not stopped that. Note: I have had 5 scans over the past 4 years and the last 4 were on the same machine and with the same technician so I've got a pretty clear view of how I'm doing DXA wise.

My bone density has declined to a worst of -4.1 t-score in the spine at my most recent scan. I have not fractured unless there are silent thoracic fractures. I wish DXA scans were better with no inconsistencies or worries about accuracy. I wish all the factors were known about how bone density and bone quality and bone strength and bone mass and yet unknown factors effected the risk of fracturing. BTW my TBS score is also bad. Not sure which TBS numbers are most relevant but I ranged from L1 0.984 to L4 at 1.305. My TBS scores did actually improve slightly. Still no fractures and plenty of opportunity for them. It is all frustratingly imperfect.
Still so glad I haven't fractured.

I think we have to be aware of the imperfections in all this and analyze the tests value and accuracy as best we can. And of course get the best help we can to help us sort this out. Despite the issues surrounding DXA scans I see them as very useful and not to be ignored. It's a test that provides useful information. Unfortunately many, maybe most docs do not know how to make best use of that information. It is up to each of us to try to do that. No matter what all the other factors are rapidly decreasing bone density or a very low steady state bone density are not good.

Despite doing the full set of blood tests that Lani recommended I/we could find no underlying explanation for my high rate of decline in density. A decline I could not stop despite dietary changes and following good resistance training and other exercise protocols. I chose to take Evenity and have had 5 shots so far. Fingers crossed. I'm still working on the dietary and exercise angles more than ever but I'm hoping this med makes a big difference.

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@awfultruth Hope you get great results from the Evenity! My score is -4.0 with no fractures. I have decided to go on Evenity because nothing I do has stopped the decrease and I have had two endocrinologists, two PCPs and a gynecologist, during the years leading up to my decision, assure me I would fracture if I didn’t use bone meds. I give in . I would like to know if you have had any insomnia or weight gain from Evenity?

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awfultruth | @awfultruth | 1 hour ago

Hi. I had great results with Evenity, 30% in my lumbar spine and very modest gains in my hips. My spine had been my worst area by far.
I had no side effects worth mentioning with Evenity.
Before I give answers to your specific side effects questions I want to say that I have a different take on Evenity side effects than most. To be blunt I do not believe that most folks appreciate how difficult it is to accurately observe and be sure of "the source" of what might be a side effect. I'm not arguing that no one has serious side effects from Evenity. I cannot know whether they do or not. But I do think the discussions in bone groups makes it seem like all kinds of side effects are happening all the time because of Evenity. People list their side effects and it appears pretty awful in some discussions.
Many of the side effects are of little or no consequence in the scheme of things but when you list all those little side effects along with a much smaller number of more significant side effects it sounds like something bad is happening.

I believe the truth is that most people have very modest side effects and most people get very good bone improvements with Evenity. That's what the studies show. I think the groups and forums tend to attract those who believe (and may or may not have had) significant negative reactions to Evenity. I also think it is just very difficult for anyone to know for sure when some types of symptoms are a side effect of a med.

So, did I have insomnia - didn't notice that one.

Did I gain weight - yes I gained weight. But here's an example of the difficulty in knowing the cause.
I did gain weight while on Evenity and afterwards. A good portion seemed to be belly fat. Darn it! But was it the Evenity? On thinking it over I realized other major changes had happened in my life in that time period. The most interesting was that I had been extremely food sensitive for 40 plus years. I could eat a very limited number of foods. I had been very slowly improving over the last few years but during my time on Evenity I had a dramatic reduction in those sensitivities. I became able to eat all kinds of foods that I had not eaten for 40 years. So, while on Evenity I started eating and enjoying all these new foods, many of which were much higher calorie foods than what I had previously been eating.

So should I blame Evenity for my new belly fat or should I praise Evenity for greatly reducing my food sensitivities? By the way, where are the discussions of positive "side effects" in our groups? I wonder if more people might see curious "side effects" like my reduction in food sensitivities if we were looking for such things. As it is we are all looking for those bad side effects.
I wish you the best of luck with your bone health!

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