DEXA Scan Discrepancies: Spine improvement and hip worsened

Posted by anewyorker @anewyorker, Mar 3 8:47am

Good morning to all,

I just received my DEXA results from last week’s scan, and they were a classic good news, bad news story.

The good news is that my spine improved dramatically from a year ago, from a T score of -3.3 to -2.3. Distal radius was unchanged, femoral neck was marginally worse (-1.7 now vs. -1.3 last year).

The big change was in the hip—from -1.6 last year to -2.1.

I’ve had osteoporosis for 20 years. Recent treatment: I was on Prolia from 2020 through spring 2024, with little change in DEXA results. I stopped the Prolia and began taking Fosamax last April; the plan was to stay on that until January 2024, at which point I would switch insurance carriers to one that would cover Tymlos or Forteo.

Unfortunately, I developed very bad GERD problems and had to discontinue the Fosamax. So I was on nothing from October until January, when I began taking Tymlos. I’ve been lucky to be able to tolerate the full dosage from Day 1 with minimal side effects.

I’ve had one compression fracture, at L1, after a bad trip and fall last October. I’m doing PT to strengthen muscles ( I have a whole list of unrelated orthopedic problems that limit my mobility).

I’m 77, in quite good overall health.

So my question is whether anyone can help me understand why my spine improved so dramatically (did the Tymlos really make such a difference after only 7 weeks?) even as my hip worsened noticeably?

I should note that the two scans were done in the same place, so there shouldn’t be a huge discrepancy because no two machines give exactly the same result.

I’m sorry this is so long. All our situations are so complicated, aren’t they?

Thanks for your help.

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@anewyorker Tymlos is good for spine. Congrats on that improvement!!

MY DEXA was at 18 months so I can't comment on the 7 weeks. If the fractured L1 was included in the scan, that could throw the results off. I ask to have my fractured vertebrae excluded. Still, not sure that the fracture would make that large of a difference. Did you ask your doc and/or radiologist?

I have read that Tymlos doesn't work well after Prolia . You might watch Dr. Ben Leder's YouTube video on Combinations and Sequencing or check out Keith McCormick's recent book "Great Bones" where they go into detail on this.

It also seems as if you weren't on a medication to counteract the rebound that happens (and increase in fracture risk) when we get off Prolia, for long enough, though those months on Fosamax may have helped: your doc can tell you. ( Tymlos doesn't really help with that rebound, from what I have read and see on the aforementioned resources. )

Fosamax can reduce effectiveness of Tymlos by about 1/3, according to Leder (paraphrasing) but you weren't on it long enough most likely for that to happen.

Once on Prolia, I have been told it is hard to get off! Maybe you could do some combo of Prolia and Tymlos (see Leder's video on combos, including Forteo and Prolia). Is there a reason you stopped Prolia?

There is info on there about going from Evenity to Prolia, and the reverse which isn't anywhere as good. Let us know what your doc says! You could do a consult with McCormick too, in person or by phone.

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anewyorker,
it's great that you are on Tymlos and tolerating the full dose . You couldn't do better, so whatever we speculate here, you are on the best path.
There can be discrepancies between dxa tecs mainly because positioning is important. But further, they wouldn't or shouldn't have measured L1 because of the fracture. L1, I'd assume (because that is where your fractured) would have been your lowest score. Averaging without that vertebra would raise your total.
You are in a good place. After Prolia is a little scary. You probably did yourself a favor by starting with fosamax to counteract the flood of osteoclasts. And then gerd protected you by getting you on Tymlos. October to January was the most risky. I won't ask if it was the beginning or the end or October. At -2.1 you are osteopenic in the hip. But you are on a great drug for the hip and femur. You may have escaped the wrath of osteoporosis. Well done.

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@gently

anewyorker,
it's great that you are on Tymlos and tolerating the full dose . You couldn't do better, so whatever we speculate here, you are on the best path.
There can be discrepancies between dxa tecs mainly because positioning is important. But further, they wouldn't or shouldn't have measured L1 because of the fracture. L1, I'd assume (because that is where your fractured) would have been your lowest score. Averaging without that vertebra would raise your total.
You are in a good place. After Prolia is a little scary. You probably did yourself a favor by starting with fosamax to counteract the flood of osteoclasts. And then gerd protected you by getting you on Tymlos. October to January was the most risky. I won't ask if it was the beginning or the end or October. At -2.1 you are osteopenic in the hip. But you are on a great drug for the hip and femur. You may have escaped the wrath of osteoporosis. Well done.

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I thought a fracture made the bone density look better-? Will double check.

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Definitely would, but they shouldn't be including a number for the fractured level.

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@gently

Definitely would, but they shouldn't be including a number for the fractured level.

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Yes and the score is adjusted down or computed only from L2-5 if possible. I have 3 lumbar fractures so there isn't much left to scan! 🙂

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@windyshores

Yes and the score is adjusted down or computed only from L2-5 if possible. I have 3 lumbar fractures so there isn't much left to scan! 🙂

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I have no idea whether they included L1 in the calculation for the spine; the report is silent on that. But it’s a good question to ask my endocrinologist when I see her on Thursday. Thanks for the input.

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@anewyorker

I have no idea whether they included L1 in the calculation for the spine; the report is silent on that. But it’s a good question to ask my endocrinologist when I see her on Thursday. Thanks for the input.

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@anewyorker you can see it on your reports I think. Or maybe the images. Sorry I forget! If you see L1-L5 with the score, that means L1 was included. The technician should have double checked with you on which vertebra was fractured.

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I’ve checked the report and it says only “Spine.” I don’t believe I have access to the images. But I will absolutely ask my doctor this week.

Too bad! I was so happy to see the excellent results ! I should have known that an improvement from -3.3 to -2.3 was too good to be true.

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@anewyorker

I’ve checked the report and it says only “Spine.” I don’t believe I have access to the images. But I will absolutely ask my doctor this week.

Too bad! I was so happy to see the excellent results ! I should have known that an improvement from -3.3 to -2.3 was too good to be true.

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The inclusion of one fracture won't make that much of a difference. Congrats on your gains! You asked how 7 weeks could do that and it's fantastic.

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@windyshores

Yes and the score is adjusted down or computed only from L2-5 if possible. I have 3 lumbar fractures so there isn't much left to scan! 🙂

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May I ask what your spine Dexa scores were before the fractures?
So Sorry to hear of your fractures.
Are they painful?

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