Accuracy of DEXA Scans

Posted by njhornung @normahorn, Mar 9 7:07pm

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.

@windyshores

@mayblin it wasn't a study. It was speculation in an interesting article. If I find it I'll share it.

@rola those are nice words but I hope you find a doctor you trust. They know way way more than I do. I just post on my own experience and share resources!

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I know Windy... and I understand, this is what I feel comfortable with moving forward. I'm still looking for a specialist, they are far and few between. At least this Dr saw my point with the bone builder and is willing prescribe.

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@ripley

Here's a link to the article I quoted, from 2015.
The drugs mentioned are bisphosphonates, Denosumab (Prolia) and strontium ranelate. https://www.bmj.com/bmj/section-pdf/897225?path=/bmj/350/8010/Analysis.full.pdf

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So I read the article claiming over diagnosis and over use of meds to reduce fractures. The article was exasperating for me. While I avoid drugs just about as much as I possibly can and have done so my entire adult life, I do want to be logical and clear headed about it. This article had something illogical and or misleadingly presented, in just about every section. For example in it's main highlighted points it listed that more fractures occur with osteopenia than osteoporosis implying - well implying what? That we should not be trying so hard to reduce fractures in those with osteoporosis? Or maybe that we should be treating osteopenia even more than osteoporosis? But the main flaw in invoking this statistic as a meaningful argument is that the likely reason for that occurring is that roughly 3.5 times more people have osteopenia than osteoporosis. So yeah, it may happen more often with osteopenia simply because more people have that level of bone thinning. Does anyone think if 3.5 times more people suddenly had osteoporosis that the fracture rates would not go up?

There are numerous examples of that kind of sloppy thinking in this paper. They state the following: "The substantive approaches to preventing hip fractures have not changed
in nearly 25 years: stop smoking, be active, and eat well. This advice works for anyone,
regardless of bone fragility, and the benefits encompass the entire human body." They seem to rate not smoking as the most powerful factor, more important than bone density they say. So their key suggestion to help the masses does not work if you are a non-smoker.
And of course it does not work for so many of us. I've never smoked, exercise a lot and eat as well as possible with food sensitivities and my bone density just keeps going down. I see the same on bone health forums all the time. People doing everything right and still they have osteoporosis. And what about hormones - I thought everyone in the medical world should know how important hormones are in having healthy bones.

One responder to the article had this suggestion: "Anyone who finds the arguments advanced by Jarvinen et al even slightly persuasive should first read the rebuttal published in Osteoporosis International (July 2015) by Dr Juliet Compston (Cambridge) before forming a personal view of the validity of Jarvinen et al's arguments." Unfortunately I could not find this rebuttal online. Of course an article you can't see is no proof but I just wanted to point out that leaders in the field were highly critical of this paper - not just yours truly.

Finally I just want to say the paper is strictly from the viewpoint of public health. As in can we cost effectively prevent fractures in large numbers of people using DXA, FRAX, and bisphosphonates. They are not considering whether you or I with our DXA scores and medical histories and how fit we are and what our balance is like and how often do we fall, could benefit from anything. They are making broad judgements for vast numbers of people which may not correspond to what's best for any given individual at all. Stop smoking, be active and eat well is just not enough.

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@windyshores

@rola your spine is slightly worse than hip, though the difference is probably not clinically significant. Tymlos is good for spine. You could do Tymlos for two years and by that time it may be more mainstream to do Evenity afterward. I had to convince my doc.

My idea was to do Evenity for just a few months, when it is a strong bone builder and before it becomes more of an anti-resorptive, so I wanted to do it after Tymlos, do a few months, then switch to Reclast. My doc told me I am creating my own protocol. Luckily both my endos don't mind but I am kind of a special case with lots of fractures and several health conditions and sensitivities.

Anyway I recently read something interesting: that in the future short courses of Evenity might be used to build bone, between other meds. That is kind of what I had in mind.

Tymlos is not an anti-resorptive and builds quality bone. That is why I chose it. Evenity is both an anabolic (first half) and anti-resorptive (second half). My reasoning, not yet checked with doc, is that if I am going to do an anti-resorptive after Tymlos it might as well be Reclast, which "locks in gains." So I will stop Evenity and switch at some point. Yes this is unusual. Yes my doc has not prescribed this protocol as yet. This strategy is more appealing to me because I am having side effects with Evenity, and I will ask to switch to Reclast on that basis alone.

The science of all this is very complex and I am not trained to interpret studies, though I read them. I want to emphasize that everything I do is obviously sanctioned by docs, since they prescribe, and that I discuss things fully with them. In other words I am not a rogue patient but probably a difficult one!

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windyshores,
The doctors should appreciate you. Any doctor who has a problem with their patient being educated is, in fact, part of the problem.
I am unhappy with my endocrinologist because he was so disinterested in our last meeting. I was already angry at the rheumatologist because he entered the room saying,”Your bones suck.” I felt that this was pretty flip on his part.
I need some additional bloodwork ordered as I bear down on Evenity dose #11 and I’m going to ask my GP to order it. 😡

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@windyshores

@rola your spine is slightly worse than hip, though the difference is probably not clinically significant. Tymlos is good for spine. You could do Tymlos for two years and by that time it may be more mainstream to do Evenity afterward. I had to convince my doc.

My idea was to do Evenity for just a few months, when it is a strong bone builder and before it becomes more of an anti-resorptive, so I wanted to do it after Tymlos, do a few months, then switch to Reclast. My doc told me I am creating my own protocol. Luckily both my endos don't mind but I am kind of a special case with lots of fractures and several health conditions and sensitivities.

Anyway I recently read something interesting: that in the future short courses of Evenity might be used to build bone, between other meds. That is kind of what I had in mind.

Tymlos is not an anti-resorptive and builds quality bone. That is why I chose it. Evenity is both an anabolic (first half) and anti-resorptive (second half). My reasoning, not yet checked with doc, is that if I am going to do an anti-resorptive after Tymlos it might as well be Reclast, which "locks in gains." So I will stop Evenity and switch at some point. Yes this is unusual. Yes my doc has not prescribed this protocol as yet. This strategy is more appealing to me because I am having side effects with Evenity, and I will ask to switch to Reclast on that basis alone.

The science of all this is very complex and I am not trained to interpret studies, though I read them. I want to emphasize that everything I do is obviously sanctioned by docs, since they prescribe, and that I discuss things fully with them. In other words I am not a rogue patient but probably a difficult one!

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Note: Please excuse me if I am repeating information said by others but although I have recently been unable to carve out time to read entries on this site, I felt compelled to respond here.

I, too, want to thank Windyshores for suggesting that I get a second opinion after responding to my thread where I questioned my doctor's suggestion about taking Evenity after stopping Prolia. I was already unsure about taking it so I decided to take another dose of Prolia in order to have time to research the options. I went out of town (returned this past Tuesday) to have a consultation with an endocrinologist who has had extensive experience with atypical femur fractures of which I've now two.

The most important thing that I learned was that deciding to take osteoporosis medications should not be decided on a single issue. Your age, activity level, medical history (including pre or post menopause, etiology of any previous fractures) and nutritional habits should all be taken into account. He felt that the decision to take an osteoporosis medication is a balance where you make a judgement about the percentage of chance that the treatment will help someone avoid getting a fracture from osteoporotic bones. He also said that there are people who have thin bones, as diagnosed by a Dexa Scan, who never fracture but there's no way to determine who will or will not succumb to a fracture. By example, I fell off a horse in my thirty's. I was an active person who enjoyed white water rafting, horseback riding and being out in nature. After my accident, my doctor saw my bones were thin around the healed L-2 spinal fracture from the accident and started me on Actonel. Unfortunately it was not known at that time that short time use was recommended. I was on it for decades which ended when my first atypical fracture happened. We can't know for sure but he suggested that I probably should not have been put on that drug at that time.

So now at 71 years old I've had an atypical fracture in both femurs due to osteoporosis medication. (put on Prolia 10 years ago). In my consult, it was recommended that I get off all osteoporosis medications. My plan is to stop prolia, take Alendronate to for 18 months and then take a drug holiday. That sounds right for me given my situation. But I would like to echo the suggestion of Windyshores and suggest that you consider a medical consultation to help you make your decision.

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@rola

Yes, my most recent DXA/VFA from Cleveland clinic in Vero Beach Fl.

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Is that the amount for which the Clinic billed your insurance? Or it that the amount that the insurance paid? The difference is often breath-taking but the Explanation of Benefits should give you this info.

And if you are on Medicare, you likely had no co-pay, is that correct? If not, what was your co-pay on Medicare, and if not on Medicare, how much was out of your pocket for this procedure?

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@doglover71

Note: Please excuse me if I am repeating information said by others but although I have recently been unable to carve out time to read entries on this site, I felt compelled to respond here.

I, too, want to thank Windyshores for suggesting that I get a second opinion after responding to my thread where I questioned my doctor's suggestion about taking Evenity after stopping Prolia. I was already unsure about taking it so I decided to take another dose of Prolia in order to have time to research the options. I went out of town (returned this past Tuesday) to have a consultation with an endocrinologist who has had extensive experience with atypical femur fractures of which I've now two.

The most important thing that I learned was that deciding to take osteoporosis medications should not be decided on a single issue. Your age, activity level, medical history (including pre or post menopause, etiology of any previous fractures) and nutritional habits should all be taken into account. He felt that the decision to take an osteoporosis medication is a balance where you make a judgement about the percentage of chance that the treatment will help someone avoid getting a fracture from osteoporotic bones. He also said that there are people who have thin bones, as diagnosed by a Dexa Scan, who never fracture but there's no way to determine who will or will not succumb to a fracture. By example, I fell off a horse in my thirty's. I was an active person who enjoyed white water rafting, horseback riding and being out in nature. After my accident, my doctor saw my bones were thin around the healed L-2 spinal fracture from the accident and started me on Actonel. Unfortunately it was not known at that time that short time use was recommended. I was on it for decades which ended when my first atypical fracture happened. We can't know for sure but he suggested that I probably should not have been put on that drug at that time.

So now at 71 years old I've had an atypical fracture in both femurs due to osteoporosis medication. (put on Prolia 10 years ago). In my consult, it was recommended that I get off all osteoporosis medications. My plan is to stop prolia, take Alendronate to for 18 months and then take a drug holiday. That sounds right for me given my situation. But I would like to echo the suggestion of Windyshores and suggest that you consider a medical consultation to help you make your decision.

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So all your previous treatment for your situation was prescribed by your PCP? Best of luck with your strategy now....I am thinking of a similar approach but I am now in osteopenia territory. Have no sense about your DEXA score.

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What I have learned from Comments is that making a medication decision based solely on Dexa is not prudent. At the very least, it seems that blood biomarkers should be taken and after a few months, re-taken to compare and figure out how you are losing bone density. Plus analysis of all the other considerations listed in doglover71's recent post.

Are you consulting only with your PCP?

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@rjd

So all your previous treatment for your situation was prescribed by your PCP? Best of luck with your strategy now....I am thinking of a similar approach but I am now in osteopenia territory. Have no sense about your DEXA score.

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Great question! All of the decisions to initiate and refill my prescriptions were from my PCP's until 3 years ago. I went to a rheumatology practice about 3 years ago when my health insurance would no longer cover my Prolia shots unless I went to a specialist. After my second atypical fracture which occurred on 11/26/2023, we had a discussion to which she admitted needing more information to decide what to do. I had already found this website which started me on the road to find out more about what I should do.

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@mayblin

windyshores if you see clinical trial results come out for short courses of evenity between other meds, please share. Thanks a lot!

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Mayblin here is a clinical trial that is looking at shorter courses of Evenity. It appears to have started in late 2023. The results won't be in until 2026 unfortunately (if it stays on schedule).

"The study will investigate if it is possible to maximize the effect of romosozumab by giving it in 2 periods of 6 months interrupted by zoledronate for 12 months compared to romosozumab for 12 months uninterrupted followed by zoledronate for 12 months. The investigators will also evaluate if 6 months of romosozumab followed by 18 months of zoledronate is non-inferior to the standard regimen of romosozumab for 12 months followed by zoledronate for 12 months."

Links (both are about the same study):
https://ctv.veeva.com/study/the-optimised-use-of-romozosumab-study
https://classic.clinicaltrials.gov/ct2/show/NCT06059222

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@doglover71

Great question! All of the decisions to initiate and refill my prescriptions were from my PCP's until 3 years ago. I went to a rheumatology practice about 3 years ago when my health insurance would no longer cover my Prolia shots unless I went to a specialist. After my second atypical fracture which occurred on 11/26/2023, we had a discussion to which she admitted needing more information to decide what to do. I had already found this website which started me on the road to find out more about what I should do.

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Forgot to mention, I also have one have one place on my Dexa Scan that shows as osteopenia.

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